JP2009156146A - Exhaust gas recirculation device and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas recirculation device capable of using efficiently cooled exhaust gas. <P>SOLUTION: The exhaust gas recirculation device includes: a first exhaust extraction route EGR1 for extracting exhaust gas from engine 101 before it enters turbocharger 103 and directing it to engine intake 111; a second exhaust extraction route EGR 2 for extracting exhaust gas that has been cooled by passing through turbocharger 103, muffler 115 and the body frame 121 and directing it to the engine intake; and valves V1 and V2 for controlling, based on operation conditions of the engine, a flow of exhaust gas directed to the engine intake by means of first exhaust extraction route EGR1 and second exhaust extraction route EGR2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust gas recirculation device and a vehicle, and more particularly to an exhaust gas recirculation device and a vehicle that take exhaust from an engine and send it to engine intake air.

  2. Description of the Related Art In an engine such as an automobile, an EGR (Exhaust Gas Recirculation) device that extracts a part of exhaust gas from the exhaust side and sends it to the intake side of the engine is known. This is to reduce the generation of NOx (nitrogen oxide) by suppressing combustion of the fuel in the engine by the exhaust gas and lowering the combustion temperature.

  FIG. 14 is a diagram showing a configuration of a conventional EGR apparatus.

  In the figure, the arrows indicate the flow paths of gas and the like in the pipe. The engine 101 has an intake manifold 111 connected to the intake side and an exhaust manifold 109 connected to the exhaust side. A portion of the exhaust before entering the exhaust manifold 109 is sent to the intake manifold 111 via the flow rate adjusting valve V1, the EGR cooler 301, and the pressure adjusting valve V3 by the exhaust extraction path EGR1.

  By flowing cooling water through the EGR cooler 301, the temperature of the high-temperature exhaust gas in the exhaust extraction path EGR1 is lowered.

  The flow rate adjusting valve V1 is a valve for controlling the amount of exhaust gas extracted from the exhaust side. The pressure adjustment valve V3 serves as an intake throttle, and is a valve for preventing the exhaust gas in the exhaust extraction path EGR1 from flowing backward.

  In such an EGR device, a part of the exhaust extraction path EGR1 is formed in the head cylinder.

  Patent Document 1 below discloses an EGR device that extracts a part of exhaust gas from the exhaust side and recirculates it to the intake side. A water-cooled EGR cooler is installed in the middle of the EGR pipe. An air-cooled EGR cooler is installed downstream of the water-cooled EGR cooler.

  In the technology of Patent Document 1, the exhaust gas recirculated to the intake side is cooled to about a few hundred degrees Celsius by heat exchange with cooling water in a water-cooled EGR cooler, and then heated with outside air in an air-cooled EGR cooler. It is cooled to several tens of degrees Celsius by replacement. Thereby, the temperature of the exhaust gas can be reduced to a temperature lower than the temperature of the cooling water for engine cooling (about 80 ° C.).

  In the following Patent Document 2, a start control device for a diesel engine is disclosed.

  When the diesel engine shifts to the idling stop state, the temperature of air present in the engine room or in the piping of the intake system including the intercooler bypass is higher than the outside air. The technique of Patent Document 2 utilizes this, and supplies high-temperature air as intake air to the combustion chamber of the engine body.

  In Patent Document 3 below, during cold start and during low load operation, exhaust gas (hot EGR gas) that is not cooled by the EGR cooler is introduced into the engine intake side to activate combustion, and HC, white smoke, etc. are generated. An exhaust gas recirculation device for suppressing the above is disclosed.

Patent Document 4 below discloses an engine exhaust gas recirculation device in which an exhaust gas cooling heat exchanger is disposed in a part of a passage for returning exhaust gas to intake air.
JP 2002-188526 A JP 2006-46199 A Japanese Patent Laid-Open No. 11-200955 Japanese Patent Laid-Open No. 7-166773

  The purpose of EGR is mainly to reduce NOx in exhaust gas and to reduce fuel consumption. For this purpose, EGR is more effective as the exhaust gas is cooled.

  However, the technique of the above-mentioned Patent Document 1 has a problem that the number of parts including piping is increased and the cost is increased because the cooler for cooling the exhaust gas in a high temperature state immediately after the engine is discharged is installed in two stages. . Further, there is a problem that the EGR route is complicated and the assembling property and the maintenance property are poor.

  Furthermore, since there is no bypass of the EGR cooler, there is a problem that the exhaust gas cannot be used while it is warm. When the engine is cold started, it is effective to raise the temperature of the intake air flowing into the cylinder as a countermeasure against exhaust smoke. Conventionally, the in-cylinder temperature has been raised by the heat generated by the glow plug, but the technique of Patent Document 1 always cools the exhaust gas.

  Further, the technique of Patent Document 2 has the following problems. The air remaining in the engine room and the intake system is warm, but it is insufficient and insufficient for realizing ignition that does not require high in-cylinder pressure.

  The effect of improving the startability is greater when in-cylinder compressed air that can obtain a higher temperature state is allowed to flow into the cylinder. However, the technique of Patent Document 2 cannot perform such an operation.

  According to the technique of Patent Document 3, warm exhaust gas can be directly introduced into the intake air without using an EGR cooler when starting the engine. When the load is high, the exhaust gas cooled via the EGR cooler can be introduced into the intake air. However, the exhaust gas is taken out only at one location immediately after the exhaust from the cylinder. The exhaust gas at this position is hot, and a large cooler is required for sufficient cooling.

  Also in the technique of Patent Document 4, the exhaust gas extraction position is only one place (exhaust manifold) immediately after discharge from the cylinder, and a large cooler is required to sufficiently cool the exhaust gas.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an exhaust gas recirculation device and a vehicle that can use efficiently cooled exhaust gas.

  According to one aspect of the present invention to achieve the above object, the exhaust gas recirculation device takes out the exhaust from the engine at least before it enters the turbocharger, and sends it to the engine intake air. A second exhaust extraction path for taking out exhaust after leaving at least the turbocharger and sending it to the engine intake air, and a first exhaust extraction path and a second exhaust extraction path in accordance with the operating condition of the engine, And control means for controlling the flow of exhaust gas sent to the engine intake air.

  According to the present invention, the exhaust extraction position from the engine differs between the first exhaust extraction path and the second exhaust extraction path. Thereby, it is possible to send a relatively high temperature exhaust and a relatively low temperature exhaust to the engine intake. Further, by exhausting at least the exhaust after having exited the turbocharger by the second exhaust extraction path, it is possible to use the efficiently cooled exhaust for engine intake.

  Preferably, the first exhaust extraction path sends exhaust from the engine downstream of the turbocharger compressor, and the second exhaust extraction path sends exhaust from the engine upstream of the turbocharger compressor.

  By adopting such a configuration, the high-pressure exhaust gas extracted before entering the turbocharger can be sent to the downstream side of the high-pressure compressor. Also, at least the relatively low pressure exhaust after leaving the turbocharger can be sent to the upstream side of the low pressure turbocharger compressor.

  According to another aspect of the present invention, the exhaust gas recirculation device extracts exhaust from the engine at least before it enters the muffler and sends it to the engine intake, and at least via the muffler. A second exhaust extraction path for extracting exhaust gas and sending it to the engine intake air, and a flow of exhaust gas sent to the engine intake air through the first exhaust extraction path and the second exhaust extraction path according to the engine operating conditions. Control means for controlling.

  According to the present invention, the exhaust extraction position from the engine differs between the first exhaust extraction path and the second exhaust extraction path. Thereby, it is possible to send a relatively high temperature exhaust and a relatively low temperature exhaust to the engine intake. Further, by exhausting at least the exhaust via the muffler by the second exhaust extraction path, it is possible to use the exhaust cooled efficiently for engine intake.

  Preferably, the second exhaust extraction path is a path through which the extracted exhaust gas passes through the vehicle frame or a pipe attached to the frame and then is sent to the engine intake air.

  By adopting such a configuration, the extracted exhaust can be passed through the frame of the vehicle or the pipe attached to the frame. Thereby, the cooled exhaust gas can be efficiently sent to the engine intake air.

  According to still another aspect of the present invention, the exhaust gas recirculation device extracts exhaust from the engine at least before it enters the muffler and sends it to the engine intake, and exhaust from the engine. Is taken downstream from the take-out position of the first exhaust take-out path, and after passing it through the vehicle frame or a pipe attached to the frame, the second exhaust take-out path is sent to the engine intake air And a control means for controlling the flow of the exhaust gas sent to the engine intake air in the first exhaust gas extraction path and the second exhaust gas extraction path in accordance with the operating state of the engine.

  According to the present invention, the exhaust extraction position from the engine differs between the first exhaust extraction path and the second exhaust extraction path. Thereby, it is possible to send a relatively high temperature exhaust and a relatively low temperature exhaust to the engine intake. Further, the exhaust after cooling is sent to the engine intake by passing through the frame of the vehicle or the pipe attached to the frame by the second exhaust extraction path, so that the efficiently cooled exhaust is sent to the engine. It can be used for intake.

  Preferably, the exhaust gas recirculation device further includes a third exhaust extraction path for mixing the exhaust passing through the first exhaust extraction path and the exhaust passing through the second exhaust extraction path, and the control means includes the engine The flow of the exhaust gas in the third exhaust extraction path is controlled in accordance with the operation status of

  In this way, by providing the third exhaust extraction path for mixing the exhaust passing through the first exhaust extraction path and the exhaust passing through the second exhaust extraction path, the state of the exhaust sent to the engine intake air can be made finer. It becomes possible to control.

  According to still another aspect of the present invention, an exhaust gas recirculation device introduces exhaust from an engine, a member having a function of cooling the exhaust, and an exhaust cooled by the member having a function of cooling, into engine intake. The member having an exhaust extraction path to be sent and having a cooling function is a turbocharger, a muffler, a vehicle frame, or a pipe attached to the frame.

  According to the present invention, the exhaust from the engine can be cooled by any one of a turbocharger, a muffler, a vehicle frame, or a pipe attached to the frame. A recirculation device can be provided.

  According to still another aspect of the present invention, a vehicle includes an engine and the exhaust gas recirculation device according to any one of the above-described ones connected to the engine.

  According to the present invention, it is possible to provide a vehicle capable of sending a relatively high temperature exhaust and a relatively low temperature exhaust to the engine intake, and using the efficiently cooled exhaust for the engine intake. it can.

  Embodiments of the present invention will be described below.

  [Overview]

  An engine provided with an exhaust gas recirculation device in an embodiment of the present invention has at least two exhaust extraction paths. The exhaust extraction position of the exhaust extraction path EGR1 is a portion (high temperature portion) where the exhaust gas is at a high temperature such as immediately after the exhaust valve. The exhaust extraction position of the exhaust extraction path EGR2 is a portion where the exhaust gas in the middle of the exhaust pipe is cooled (low temperature portion). The exhaust extraction path to be used is switched according to the engine operating status.

  The high-temperature exhaust gas extracted through the exhaust gas extraction path EGR1 is used when starting the engine. The low-temperature exhaust gas extracted through the exhaust gas extraction path EGR2 is used when the load is high.

  For example, the exhaust extraction position in the high temperature part can be any position between the exhaust port and the turbocharger, and the exhaust extraction position in the low temperature part can be any position downstream of the turbocharger.

  Or, the exhaust extraction position of the high temperature part should be at least the position before exhaust enters the muffler, and the exhaust extraction position of the low temperature part should be at least the position after the exhaust gas passes through the muffler (near the muffler outlet). it can.

  Further, the exhaust extraction path EGR2 can be a path for cooling the extracted exhaust by passing it through a frame of a vehicle or a pipe attached to the frame and then sending it to the engine intake air.

  [First Embodiment]

  FIG. 1 is a diagram showing a configuration of an exhaust gas recirculation device for a motorcycle (an example of a saddle-ride type vehicle) according to a first embodiment of the present invention.

  Referring to the figure, an exhaust gas recirculation device compresses intake air included in an engine 101 (here, a four-cylinder diesel engine is assumed), an air cleaner 107 that cleans intake air, and a turbocharger 103. A compressor 103b, an intercooler 105 that cools the compressed air, an intake manifold 111 that sends the cooled air to each cylinder of the engine, an exhaust manifold 109 that collects exhaust from each cylinder of the engine 101, and a turbocharger 103 The turbine 103a for rotating the compressor 103b by exhaust, the exhaust pipe 113 for sending the exhaust from the turbine 103a, the muffler 115 for silencing the exhaust, and the automatic cooling for part of the exhaust from the muffler 115 are included. Two wheels A body frame 121 of, and an EGR cooler 123 for cooling the exhaust gas after the heat dissipation is performed by the frame 121.

  The exhaust extraction path EGR1 is a path for mixing the exhaust gas immediately after exiting the exhaust manifold 109 (or immediately after exiting the engine 101) with the air entering the intake manifold 111 after exiting the intercooler 105.

  The exhaust extraction path EGR2 cools the exhaust gas from the exhaust manifold 109 by the turbine 103a, the exhaust pipe 113, the muffler 115, the frame 121, and the EGR cooler 123, and mixes it with the air that has exited the air cleaner 107. This is the route.

  Further, a valve V1 for adjusting the flow rate of the exhaust gas in the exhaust extraction route EGR1 is adjusted in the middle of the exhaust extraction route EGR1, and the flow rate of the exhaust gas in the exhaust extraction route EGR2 is adjusted in the middle of the exhaust extraction route EGR2. A valve V2 is provided for each.

  A throttle S for adjusting the amount of air sent to the engine before the position where the pipe extending from the outlet of the intercooler 105 intersects the exhaust extraction path EGR1 to prevent the backflow of exhaust gas from the exhaust extraction path EGR1 to the intercooler 105 side. Is provided.

  FIG. 2 is a side view of a motorcycle equipped with the exhaust gas recirculation device of FIG.

  As shown in the figure, an EGR cooler 123 is attached to a cowl on the front wheel 151. It is desirable to mount the EGR cooler 123 in front of the vehicle body, for example, before the front fork. A muffler 115 is attached on the rear wheel 153.

  The exhaust extraction route EGR1 is provided as a route for mixing the exhaust gas immediately after exiting the engine 101 with the intake air of the engine 101. A frame 121 constituting a part of the exhaust extraction path EGR2 also serves as a body frame of the motorcycle.

  Further, in the middle of the frame 121, a path 125 for draining water and sooting is provided. This causes water and soot to fall naturally at the lowest point in the middle of the frame, which is in the middle of the EGR path.

  That is, a volume body (small chamber) for temporarily retaining the exhaust gas is provided at a place where the frame 121 is bent downward (traveling surface direction). The flow rate of air entering the chamber is reduced. Thereby, condensed water and soot accumulate in a small chamber. Water and soot are discharged to the outside through a path 125 from a small-diameter hole penetrating the small chamber and the outside. The mechanism for discharging the condensed water and soot is structurally the same as the drain attached to the silencer of the engine.

  FIG. 3 is a side view of the frame 121.

  Here, a frame 121 having a hollow structure is used. Dotted lines in the figure indicate partitions in the frame. The arrows indicate the exhaust gas path.

  An exhaust gas inlet 121a for introducing exhaust gas from the muffler 115, an exhaust gas outlet 121b for sending exhaust gas to the EGR cooler 123, and an exhaust gas from the EGR cooler 123 are introduced into the frame 121. Exhaust gas inlet 121c and an exhaust gas outlet 121d for sending exhaust gas to the engine are provided.

  The frame is preferably made of SUS pipe to prevent corrosion. Both the iron frame and the aluminum frame have a hollow structure, and if the inner wall of the exhaust passage is treated to prevent corrosion, it can be applied as an exhaust gas passage regardless of the material and the manufacturing method.

  Further, if the frame has a hollow passage in a part thereof, it can be used as an exhaust gas path, and heat can be radiated from the frame.

  In the case of a casting frame having no hollow part, an exhaust gas path made of SUS pipe is fixed in contact with the frame, whereby an exhaust gas path integrated with the frame can be obtained. That is, also in this case, the heat radiation area can be secured, and a higher exhaust gas cooling effect can be obtained as compared with the case where the exhaust gas path is constituted by a single pipe. Also, fixing the pipe integrally to the frame is effective in increasing the strength of the frame itself.

  FIG. 4 is a block diagram of a control circuit of the exhaust gas recirculation device of FIG.

  The exhaust gas recirculation device includes an engine control unit 201 for controlling the electric system of the vehicle, an engine speed sensor 203 for measuring the engine speed, and an accelerator position sensor 205 for detecting the accelerator position. A cooling water temperature sensor 207 for detecting the temperature of the cooling water, an oil temperature sensor 209 for detecting the temperature of the oil, and an intake air temperature sensor 211 for detecting the temperature of the intake air are connected.

  Note that only the output of either the coolant temperature sensor 207 or the oil temperature sensor 209 may be used for controlling the exhaust gas recirculation device.

  In order to prevent the reverse flow of the exhaust gas by the engine control unit 201, the valve V1 for adjusting the flow rate of the exhaust gas in the exhaust extraction path EGR1, the valve V2 for adjusting the flow rate of the exhaust gas in the exhaust extraction path EGR2, and the like. The throttle S is controlled.

  FIG. 5 is a flowchart showing the control executed by the exhaust gas recirculation device when starting the engine.

  When the engine key is turned on in step S101, it is determined in step S103 whether the coolant temperature or the oil temperature is 30 ° C. or less.

  If YES in step S103, the valve V1 of the exhaust extraction path EGR1 is fully opened and the valve V2 of the exhaust extraction path EGR2 is pre-closed in step S105.

  On the other hand, if NO in step S103, the valve V1 of the exhaust extraction path EGR1 is fully closed and the valve V2 of the exhaust extraction path EGR2 is opened in step S117.

  If the starter switch is turned on in step S107, the cell motor of the engine is rotated in step S109, thereby starting crank rotation.

  In step S111, the process waits until the crank rotational speed becomes equal to or higher than the target value. In step S113, fuel injection is started, and combustion in the cylinder is started.

  In step S115, the fuel injection amount, the fuel injection timing, the number of fuel injections, and the fuel injection pressure are changed based on the sensor detection value and the like. Further, the engine speed, the accelerator opening, the coolant temperature or the oil temperature, and the intake air temperature are detected, and the opening of the valve V1 of the exhaust extraction path EGR1 and the opening of the valve V2 of the exhaust extraction path EGR2 according to the combination conditions of the detected values. To change the state of introduction of exhaust gas into the engine.

  FIG. 6 is a diagram showing the control in step S115 of FIG.

  Here, (a) the cooling water temperature or oil temperature is less than 20 ° C. (cooled state), (b) the cooling water temperature or oil temperature is 20 ° C. or more and less than 60 ° C., (c) the cooling water temperature or oil temperature is 60 ° C. Assuming the above states (warm-up state), it is shown how the engine control unit 201 adjusts the openings of the valves V1 and V2 from the accelerator opening and the engine speed in each state. ing. In each state, the following control is performed.

  (A) When the cooling water temperature or oil temperature is less than 20 ° C. (cooled state)

  Regardless of the accelerator opening and the engine speed, the valve V1 is opened and the valve V2 is fully closed, so that only the exhaust gas in the exhaust extraction path EGR1 is sent to the engine. This is to warm up the cold engine.

  (B) When the cooling water temperature or oil temperature is 20 ° C or higher and lower than 60 ° C

  The flow rates of the valves V1 and V2 are controlled according to the accelerator opening and the engine speed.

  That is, if the accelerator opening is fully open, regardless of the engine speed, the valve V1 is fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  If the accelerator opening is medium open and the engine speed is the lowest or medium speed, the exhaust gas in the exhaust extraction path EGR1 and the exhaust gas in the exhaust extraction path EGR2 are opened by opening the valve V1 and the valve V2. Send both to the engine.

  If the accelerator opening is medium open and the engine speed is the maximum, the valve V1 is fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  If the accelerator opening is fully closed and the engine speed is the minimum, the valve V1 is opened and the valve V2 is fully closed, so that only the exhaust gas in the exhaust extraction path EGR1 is sent to the engine.

  If the accelerator opening is fully closed and the engine speed is medium, the valve V1 and the valve V2 are opened so that the exhaust gas in the exhaust extraction path EGR1 and the exhaust gas in the exhaust extraction path EGR2 are both engine. Send to.

  If the accelerator opening is fully closed and the engine speed is the maximum, the valve V1 is fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  (C) When the cooling water temperature or oil temperature is 60 ° C. or higher (warm-up state)

  Regardless of the accelerator opening and the engine speed, the valve V1 is fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  When both the exhaust gas in the exhaust extraction path EGR1 and the exhaust gas in the exhaust extraction path EGR2 are sent to the engine, the amount of exhaust gas in the exhaust extraction path EGR2 increases as the engine speed increases. Alternatively, it is desirable to adjust the mixing ratio of the exhaust gas in the exhaust extraction path EGR1 and the exhaust gas in the exhaust extraction path EGR2 so that the amount of exhaust gas in the exhaust extraction path EGR2 increases as the accelerator opening increases.

  This adjusts the amount of air-fuel mixture in each exhaust extraction path so that the intake air temperature of the engine after mixing becomes the target intake air temperature. By adjusting the temperature so that the temperature during fuel combustion becomes 1500 to 1800 (K), generation of harmful exhaust gases (CO, NOx) and smoke can be reduced.

  When the engine is started, the exhaust as EGR is used without cooling. Before starting the engine, the exhaust gas contains sufficient oxygen because the engine is not combusting. For this reason, there is no adverse effect on starting. If the fuel injection is stopped during the initial several cycles, the startability is still improved.

  [Second Embodiment]

  FIG. 7 is a diagram showing a configuration of an exhaust gas recirculation device for a motorcycle according to the second embodiment of the present invention.

  The exhaust gas recirculation device in the present embodiment is different from that in the first embodiment in that the exhaust gas immediately after exiting from the exhaust manifold 109 (immediately after exiting from the engine 101) is exhausted in the exhaust extraction path EGR2. An exhaust extraction path EGR3 for mixing with the exhaust gas is provided.

  A valve V3 for adjusting the flow rate of the exhaust gas in the exhaust extraction path EGR3 is provided in the middle of the exhaust extraction path EGR3. The hot EGR gas in the exhaust extraction path EGR3 is mixed with the gas in the exhaust extraction path EGR2 to adjust the temperature and then introduced into the intake air.

  FIG. 8 is a block diagram of a control circuit of the exhaust gas recirculation device of FIG.

  In the exhaust gas recirculation device, in addition to the configuration of the control circuit shown in FIG. 4, the engine control unit 201 controls the valve V3 for adjusting the flow rate of the exhaust gas in the exhaust extraction path EGR3.

  FIG. 9 is a diagram illustrating a method of controlling the valve of the exhaust gas recirculation device according to the second embodiment.

  Here, as in FIG. 6, (a) the cooling water temperature or oil temperature is less than 20 ° C. (cooled state), (b) the cooling water temperature or oil temperature is 20 ° C. or more and less than 60 ° C., (c) the cooling water temperature or Assuming each state where the oil temperature is 60 ° C. or higher (warm-up state), how the engine control unit 201 opens the valves V1, V2, and V3 based on the accelerator opening and the engine speed in each state. It is shown how to adjust. In each state, the following control is performed.

  (A) When the cooling water temperature or oil temperature is less than 20 ° C. (cooled state)

  Regardless of the accelerator opening and the engine speed, the valve V1 is opened and the valves V2 and V3 are fully closed, so that only the exhaust gas in the exhaust extraction path EGR1 is sent to the engine. This is to warm up the cold engine.

  (B) When the cooling water temperature or oil temperature is 20 ° C or higher and lower than 60 ° C

  The flow rates of the valves V1, V2, and V3 are controlled according to the accelerator opening and the engine speed.

  If the accelerator opening is fully open, regardless of the engine speed, the valves V1 and V3 are fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  If the accelerator opening is medium open and the engine speed is the minimum or medium speed, the valve V1 is fully closed, the valves V2 and V3 are opened, and the exhaust gas in the exhaust extraction path EGR2, and Both exhaust gases from the exhaust extraction path EGR3 are sent to the engine.

  If the accelerator opening is medium open and the engine speed is the maximum, the valves V1 and V3 are fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  If the accelerator opening is fully closed and the engine speed is the minimum, the valve V1 is opened and the valves V2 and V3 are fully closed, so that only the exhaust gas in the exhaust extraction path EGR1 is sent to the engine. .

  If the accelerator opening is fully closed and the engine speed is medium, the valve V1 is fully closed and the valve V2 and the valve V3 are opened, so that the exhaust gas in the exhaust extraction path EGR2 and the exhaust extraction path EGR3 Both exhaust gases are sent to the engine.

  If the accelerator opening is fully closed and the engine speed is the maximum, the valves V1 and V3 are fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  (C) When the cooling water temperature or oil temperature is 60 ° C. or higher (warm-up state)

  Regardless of the accelerator opening and the engine speed, the valves V1 and V3 are fully closed and the valve V2 is opened, so that only the exhaust gas in the exhaust extraction path EGR2 is sent to the engine.

  When both the exhaust gas in the exhaust extraction path EGR2 and the exhaust gas in the exhaust extraction path EGR3 are sent to the engine, the amount of exhaust gas in the exhaust extraction path EGR2 increases as the engine speed increases. Alternatively, it is desirable to adjust the mixing ratio of the exhaust gas in the exhaust extraction path EGR2 and the exhaust gas in the exhaust extraction path EGR3 so that the amount of exhaust gas in the exhaust extraction path EGR2 increases as the accelerator opening increases.

  Also in the present embodiment, the amount of air-fuel mixture in each exhaust extraction path is adjusted so that the intake air temperature of the engine after mixing becomes the target intake air temperature. By adjusting the temperature so that the temperature during fuel combustion becomes 1500 to 1800 (K), generation of harmful exhaust gases (CO, NOx) and smoke can be reduced.

  [Third Embodiment]

  FIG. 10 is a side view of a motorcycle equipped with the exhaust gas recirculation device of FIG. 1 in the third embodiment.

  Here, an embodiment in which an exhaust gas recirculation device is mounted on an off-road motorcycle is shown.

  As shown in the figure, an EGR cooler 123 is attached to the front side of the vehicle body frame. A muffler 115 is attached on the rear wheel 153.

  The exhaust extraction route EGR1 is provided as a route for mixing the exhaust gas immediately after exiting the engine 101 with the intake air of the engine 101. A frame 121 constituting a part of the exhaust extraction path EGR2 also serves as a motorcycle frame.

  Further, in the middle of the frame 121, a path 125 for draining water and sooting is provided.

  FIG. 11 is a side view of the frame 121.

  Here, a frame 121 having a hollow structure is used. In the figure, an exhaust gas path is indicated by an arrow.

  The frame 121 is provided with an exhaust gas inlet 121 a for introducing exhaust gas from the muffler 115 and an exhaust gas outlet 121 b for sending the exhaust gas to the EGR cooler 123.

  In the case of a casting frame having no hollow part, an exhaust gas path made of SUS pipe can be brought into contact with the frame and fixed, thereby providing an exhaust gas path integrated with the frame.

  [Fourth Embodiment]

  FIG. 12 is a side view of a motorcycle equipped with the exhaust gas recirculation device of FIG. 1 in the fourth embodiment.

  Here, a configuration is shown in which an exhaust gas recirculation device is mounted on a naked type motorcycle.

  As shown in the figure, an EGR cooler 123 is attached to the front side of the vehicle body frame. A muffler 115 is attached to the side of the rear wheel 153.

  The exhaust extraction route EGR1 is provided as a route for mixing the exhaust gas immediately after exiting the engine 101 with the intake air of the engine 101. A frame 121 constituting a part of the exhaust extraction path EGR2 also serves as a motorcycle frame.

  Further, in the middle of the frame 121, a path 125 for draining water and sooting is provided.

  FIG. 13 is a side view of the frame 121.

  Here, a frame 121 having a hollow structure is used. In the figure, an exhaust gas path is indicated by an arrow.

  The frame 121 is provided with an exhaust gas inlet 121a for introducing exhaust gas from the exhaust pipe 113 upstream of the muffler 115, and an exhaust gas outlet 121b for sending the exhaust gas to the EGR cooler 123.

  In the case of a casting frame having no hollow part, an exhaust gas path made of SUS pipe is fixed in contact with the frame, whereby an exhaust gas path integrated with the frame can be obtained.

  [Effects of the embodiment]

  According to the above embodiment, when it is desired to increase the intake air temperature of the engine at the time of start-up or warm-up operation, the high-temperature exhaust gas immediately after the exhaust valve can be used for EGR. Thereby, the temperature rise in a cylinder is accelerated | stimulated and the stable engine startability can be ensured.

  In addition, the temperature of the exhaust gas used as the EGR is preferably lower in order to reduce NOx and reduce fuel consumption during high-load driving during traveling. In the present embodiment, exhaust gas that has been sufficiently cooled during traveling can be introduced into the EGR.

  Further, during low and medium load operation, the two EGR paths can be mixed and the exhaust gas temperature can be set as the target temperature before being introduced into the intake air. Thereby, the amount of smoke discharged can be reduced.

  To cool the exhaust from the engine, at least one of a turbocharger, a muffler, a vehicle frame, and a pipe attached to the frame is used. Thereby, exhaust gas can be cooled efficiently.

  Further, by using the exhaust gas thus cooled, the load on the EGR cooler is reduced, and the EGR cooler can be downsized (or abolished).

  Furthermore, the number of parts of the EGR pipe can be reduced by using the frame of the vehicle body for a part of the EGR route.

  Further, exhaust gas that has passed through the muffler is passed through the frame of the vehicle body to dissipate heat to the outside air, whereby exhaust gas that has been sufficiently cooled by the muffler can be further cooled.

  In the middle of the exhaust gas passage integrated with the vehicle body frame, a volume should be provided at the lowermost part so that soot and condensate are deposited so that the deposits are naturally discharged from the communication holes. Thus, the clearance of the passage can be ensured.

  Furthermore, a smoke reduction effect can be obtained by introducing warm EGR gas into the engine intake air for a certain period of time immediately after engine startup.

  [Others]

  When crank speed is below a certain level at engine start, fuel is not injected, only air is compressed, and air that has been compressed and heated to high temperature is reintroduced into the cylinder via the EGR path May be performed.

  When the engine is started, fuel injection may be started when the crank rotational speed becomes equal to or higher than a certain value. In this case, since the inside of the cylinder is warmed when the injection is started, more stable startability can be secured.

  It is desirable that the EGR cooler is disposed at a position where the traveling wind can be used for cooling, in the front of the vehicle body or in the vicinity of the engine.

  Further, if the exhaust gas can be sufficiently cooled in the EGR path, the EGR cooler may not be provided.

  Further, it is desirable that the exhaust gas taken out immediately after the exhaust valve (upstream side of the turbocharger, high pressure part) is introduced immediately before the intake valve (high pressure part). Further, it is desirable that the exhaust gas taken out from a position such as a muffler (downstream side of the turbo, low pressure part) and cooled is introduced to the upstream side of the compressor (low pressure part). This is because the pressure can be easily adjusted by reducing the pressure between the end points of the EGR path.

  Moreover, although the example which provides a volume part in the middle of the exhaust-gas channel | path containing a vehicle body frame was demonstrated, you may install the filter structure which collects soot and condensed water with a maze shape other than a volume part. Further, the middle of the passage may be T-shaped, and water or soot may be trapped downward.

  The present invention can be applied to both an engine having a turbocharger and an engine having no turbocharger. The engine may be either diesel or gasoline.

  The present invention can also be applied to saddle riding type vehicles such as motorcycles and motorbikes. As long as it is a straddle-type vehicle, the present invention can be applied to any of a two-wheel, three-wheel, four-wheel vehicle (or a vehicle having more wheels), or a vehicle that moves by a crawler mechanism. it can. Furthermore, the present invention can be applied to a vehicle having an engine such as an automobile.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a diagram showing a configuration of an exhaust gas recirculation device for a motorcycle (an example of a saddle-ride type vehicle) according to a first embodiment of the present invention. FIG. 2 is a side view of a motorcycle equipped with the exhaust gas recirculation device of FIG. 1. 3 is a side view of a frame 121. FIG. FIG. 2 is a block diagram of a control circuit of the exhaust gas recirculation device of FIG. 1. It is a flowchart which shows the control which the exhaust-gas recirculation apparatus at the time of engine starting performs. It is a figure which shows the control in step S115 of FIG. It is a figure which shows the structure of the exhaust-gas recirculation apparatus of the motorcycle in the 2nd Embodiment of this invention. FIG. 8 is a block diagram of a control circuit of the exhaust gas recirculation device of FIG. 7. It is a figure which shows the control method of the valve | bulb of the exhaust-gas recirculation apparatus in 2nd Embodiment. FIG. 6 is a side view of a motorcycle equipped with the exhaust gas recirculation device of FIG. 1 in a third embodiment. 3 is a side view of a frame 121. FIG. FIG. 9 is a side view of a motorcycle equipped with the exhaust gas recirculation device of FIG. 1 in a fourth embodiment. 3 is a side view of a frame 121. FIG. It is a figure which shows the structure of the conventional EGR apparatus.

Explanation of symbols

101 Engine 103 Turbocharger 103a Turbine 103b Compressor 105 Intercooler 107 Air Cleaner 109 Exhaust Manifold 111 Intake Manifold 113 Exhaust Pipe 115 Muffler 121 Frame 121a Exhaust Gas Inlet 121b Exhaust Gas Outlet 121c Exhaust Gas Inlet 121d Exhaust Gas Outlet 123 EGR Cooler Control unit 203 Engine speed sensor 205 Accelerator opening sensor 207 Cooling water temperature sensor 209 Oil temperature sensor 211 Intake air temperature sensor EGR1 to EGR3 Exhaust extraction path S Throttle V1 to V3 Valve

Claims (8)

A first exhaust extraction path that extracts exhaust from the engine at least before it enters the turbocharger and sends it to the engine intake;
A second exhaust extraction path for taking out the exhaust after leaving at least the turbocharger and sending it to the engine intake air;
An exhaust gas recirculation device comprising control means for controlling a flow of exhaust gas sent to engine intake air in the first exhaust gas extraction path and the second exhaust gas extraction path in accordance with an engine operating condition. The first exhaust extraction path sends exhaust from the engine to the downstream side of the compressor of the turbocharger,
2. The exhaust gas recirculation device according to claim 1, wherein the second exhaust extraction path sends exhaust from an engine to an upstream side of a compressor of the turbocharger. A first exhaust extraction path that extracts exhaust from the engine at least before it enters the muffler and sends it to the engine intake;
A second exhaust extraction path for extracting exhaust via at least the muffler and sending it to the engine intake;
An exhaust gas recirculation device comprising control means for controlling a flow of exhaust gas sent to engine intake air in the first exhaust gas extraction path and the second exhaust gas extraction path in accordance with an engine operating condition.   The second exhaust extraction path is a path for passing the extracted exhaust through the vehicle frame or a pipe attached to the frame and then sending it to the engine intake air. The exhaust gas recirculation device according to any one of the above. A first exhaust extraction path that extracts exhaust from the engine at least before it enters the muffler and sends it to the engine intake;
Exhaust gas from the engine is taken downstream from the take-out position of the first exhaust take-out path, and after passing it through a vehicle frame or a pipe attached to the frame, it is sent to the engine intake air. 2 exhaust extraction paths,
An exhaust gas recirculation device comprising control means for controlling a flow of exhaust gas sent to engine intake air in the first exhaust gas extraction path and the second exhaust gas extraction path in accordance with an engine operating condition. A third exhaust extraction path for mixing exhaust through the first exhaust extraction path and exhaust through the second exhaust extraction path;
The exhaust gas recirculation device according to any one of claims 1 to 5, wherein the control means controls an exhaust flow of the third exhaust extraction path in accordance with an operating state of the engine. A member having a function of introducing exhaust from the engine and cooling it;
An exhaust extraction path for sending the exhaust cooled by the member having the function of cooling to the engine intake air,
The member having the function of cooling is an exhaust gas recirculation device that is one of a turbocharger, a muffler, a vehicle frame, and a pipe attached to the frame. Engine,
A vehicle comprising the exhaust gas recirculation device according to any one of claims 1 to 7, which is connected to the engine.

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