JP2007162481A - Internal combustion engine with supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine with a supercharger reducing difference of generated torque between cylinder groups in the internal combustion engine with the supercharger using only exhaust gas from a cylinder of part of cylinder group out of a plurality of cylinder groups for driving the supercharger. <P>SOLUTION: In the internal combustion engine with the supercharger using only exhaust gas from the cylinder of a part of cylinder groups 100 out of the plurality of cylinder groups 100, 200 for driving the supercharger 103, air from the supercharger 103 is supplied to only cylinders of a part of the cylinder group 100, and a generated torque difference reduction means reducing difference between torque generated by the cylinder group 100 to which air form the supercharger 103 is supplied, and torque generated by the cylinder group 200 to which air form the supercharger 103 is not supplied, is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine with a supercharger.

  Generally, in an internal combustion engine mounted on an automobile or the like, an exhaust gas purification catalyst is disposed in an exhaust gas passage, and HC (hydrocarbon), CO (carbon monoxide), NOx in the exhaust gas by the exhaust gas purification catalyst. Air pollutants such as (nitrogen oxides) are converted into water, carbon dioxide, nitrogen, etc. to purify the exhaust gas.

  As such an exhaust gas purification catalyst, for example, a three-way catalyst in which a noble metal catalyst such as platinum, rhodium, palladium or the like is supported on a carrier formed of silicon oxide or the like is widely used. If the temperature of the purification catalyst does not exceed a predetermined activation temperature (for example, 350 ° C.), sufficient exhaust gas purification performance cannot be obtained. In this regard, during normal operation when the internal combustion engine is already warmed up, the exhaust gas purifying catalyst is constantly exposed to high-temperature exhaust gas (for example, 700 to 900 ° C.) and its temperature is activated. Since it is maintained at a temperature equal to or higher than the gasification temperature, it has sufficient exhaust gas purification performance.

  However, at the time of cold start of the internal combustion engine, the exhaust gas purification catalyst is gradually warmed from normal temperature by the exhaust gas after the internal combustion engine is started, and therefore, sufficient exhaust gas purification is performed for a certain period after the internal combustion engine is started. It will not have performance. As a result, during the cold start of the internal combustion engine, the exhaust gas is not sufficiently purified until the temperature of the exhaust gas purification catalyst reaches the activation temperature (that is, the catalyst warm-up period), and HC, CO , It will be discharged into the atmosphere while containing air pollutants such as NOx. For this reason, at the time of cold start of the internal combustion engine, it is desired to quickly increase the temperature of the exhaust gas purification catalyst to the activation temperature.

  On the other hand, in order to increase the intake efficiency of the internal combustion engine and increase the output, an internal combustion engine equipped with a supercharger is known. In particular, Patent Document 1 describes an internal combustion engine that can be operated with an air-fuel ratio lean mixture, in which a supercharger is provided for the purpose of expanding the lean air-fuel ratio operation region. In general, when operating with a lean air-fuel mixture, fuel efficiency and exhaust emissions can be improved. Therefore, in such an internal combustion engine with a supercharger, both improvement in fuel efficiency and exhaust emissions and high output must be achieved. Is possible.

  By the way, as such a supercharger of an internal combustion engine, an exhaust drive type supercharger driven by an exhaust gas flow is widely used. However, in an internal combustion engine equipped with such a supercharger, the supercharger Since the energy of the exhaust gas is used to drive the exhaust gas, the temperature of the exhaust gas is lowered as compared with the case where the supercharger is not provided.

  When the temperature of the exhaust gas decreases in this way, the temperature of the exhaust gas purification catalyst disposed in the exhaust gas passage cannot be quickly increased. Therefore, particularly when the internal combustion engine is cold started, There is a concern that the catalyst warm-up property is lowered, and as a result, the exhaust gas purification becomes insufficient as compared with the case where the supercharger is not provided.

  With respect to such a problem, Patent Document 2 discloses that the exhaust gas passage can be switched between when it should be supercharged and when it is not, so that the output can be increased as necessary. An internal combustion engine with a supercharger that can ensure warm-up performance is disclosed. However, in such an internal combustion engine, the exhaust gas passage tends to increase in order to constitute an exhaust gas passage that can be switched as described above, and it is necessary to install a switching valve in the exhaust gas passage. Therefore, the cost may increase and the mountability may deteriorate. Further, the heat capacity of the exhaust gas passage increases due to an increase in the amount of exhaust pipes or the installation of a switching valve, so that the catalyst warm-up efficiency is lowered, and in fact, there is a possibility that sufficient catalyst warm-up performance cannot be improved. Furthermore, there is a problem that the control becomes complicated by performing the switching as described above.

JP 2005-69029 A Japanese Utility Model Publication 1-173423 JP-A-1-315633 JP 2003-301736 A Japanese Patent Laid-Open No. 8-232645 JP 2003-97259 A

  Further, as another configuration of the internal combustion engine with a supercharger that ensures the catalyst warm-up property, there is a configuration in which only the exhaust gas flow from some cylinders of the internal combustion engine is used to drive the supercharger. Conceivable. That is, for example, a plurality of cylinders of an internal combustion engine are divided into a first cylinder group and a second cylinder group, and the supercharger is driven only by the exhaust gas from the cylinders of the first cylinder group and the air from the supercharger The intake / exhaust passage is configured so that is supplied to the cylinders of both cylinder groups. In this way, supercharging can be carried out, and the exhaust gas from the cylinders of the second cylinder group does not drive the supercharger, so that the temperature is maintained high, and as a result, catalyst warm-up is ensured. Can do.

  However, in such a configuration, the back pressure is higher in the cylinders of the first cylinder group in which the exhaust gas is used for driving the supercharger than in the cylinders of the second cylinder group in which the exhaust gas is not used for driving the supercharger. Therefore, there is a bias in the distribution of air between the cylinder groups, and as a result, there is a case where a difference occurs in the generated torque of the cylinders between the cylinder groups, causing problems such as vibration.

  The present invention has been made in view of the above, and an object thereof is to have only a plurality of cylinder groups, and only exhaust gas from a cylinder of a part of the plurality of cylinder groups. Is an internal combustion engine with a supercharger adapted to drive a supercharger, wherein the internal combustion engine with a supercharger is configured to reduce a difference in torque generated between cylinders between cylinder groups. Is to provide.

  The present invention provides an internal combustion engine with a supercharger described in each claim as a means for solving the above-mentioned problems.

  The invention according to claim 1 has a plurality of cylinder groups, and only the exhaust gas from the cylinders of a part of the plurality of cylinder groups is used to drive the supercharger. In the internal combustion engine with a supercharger, the air from the supercharger is supplied only to the cylinders of the some cylinder groups or only to the cylinders of the cylinder groups other than the some cylinder groups. The generated torque that reduces the difference between the generated torque of the cylinders in the cylinder group that is supplied with air from the supercharger and the generated torque of the cylinders in the cylinder group that is not supplied with air from the supercharger Provided is an internal combustion engine with a supercharger, characterized by comprising a difference reducing means.

  For example, for the purpose of rapidly increasing the temperature of the exhaust gas purification catalyst disposed in the exhaust gas passage, only the exhaust gas from the cylinders of some of the plurality of cylinder groups as described above is used. In an internal combustion engine with a supercharger that is used to drive a supercharger, the exhaust gas is used to drive the supercharger in the cylinders of the cylinder group in which the exhaust gas is used to drive the supercharger. The back pressure is higher than that of the cylinders in the cylinder group that are not used. For this reason, there is a bias in the distribution of air between the cylinder groups, and as a result, there is a case where a difference occurs in the generated torque of the cylinders between the cylinder groups, causing problems such as vibration.

  On the other hand, in the first aspect of the invention, only the exhaust gas from the cylinders of a part of the plurality of cylinder groups is used to drive the turbocharger. In the internal combustion engine with a charger, the air from the supercharger is supplied only to the cylinders of the partial cylinder group or to the cylinders of a cylinder group other than the partial cylinder group. The difference between the generated torque of the cylinders of the cylinder group supplied with air from the supercharger and the generated torque of the cylinders of the cylinder group not supplied with air from the supercharger is reduced by the generated torque difference reducing means. It has become so. Therefore, according to the first aspect of the present invention, it is possible to suppress the occurrence of problems such as vibration caused by the difference in torque generated between the cylinder groups.

  According to a second aspect of the present invention, in the first aspect of the present invention, the generated torque difference reducing means supplies a cylinder of a cylinder group to which air from the supercharger is supplied and air from the supercharger. Means for controlling the intake air amount and the air-fuel ratio of the air-fuel mixture are included independently for each cylinder in the cylinder group.

  By independently controlling the intake air amount and the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group supplied with air from the supercharger and the cylinders of the cylinder group not supplied with air from the supercharger, The generated torque can be independently controlled by the cylinders of the cylinder group to which the air from the supercharger is supplied and the cylinders of the cylinder group to which the air from the supercharger is not supplied. Therefore, according to the second aspect of the present invention, the generated torque of the cylinders of the cylinder group to which the air from the supercharger is supplied and the generated torque of the cylinders of the cylinder group to which the air from the supercharger is not supplied Difference can be reduced, and the occurrence of problems such as vibration can be suppressed.

  According to a third aspect of the present invention, in the second aspect of the present invention, the amount of intake air and the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which air from the supercharger is not supplied are the air from the supercharger. The generated torque of the cylinder group to which no gas is supplied is controlled so as to coincide with the generated torque of the cylinder group of the cylinder group to which the air from the supercharger is supplied.

  According to the third aspect of the present invention, the generated torque of the cylinder group of the cylinder group to which the air from the supercharger is supplied and the generated torque of the cylinder group of the cylinder group to which the air from the supercharger is not supplied And the occurrence of problems such as vibration can be suppressed.

  According to a fourth aspect of the invention, there is provided the first or second cylinder group according to the second or third aspect of the invention, wherein only exhaust gas from the cylinders of the first cylinder group is the above. It is used to drive the supercharger and air from the supercharger is supplied only to the cylinders of the first cylinder group.

  According to the fourth aspect of the invention, the cylinders of the first cylinder group are supercharged. Therefore, the air-fuel ratio of the air-fuel mixture is increased to a larger required torque than when supercharging is not performed. You can drive with leaner. As a result, the fuel consumption can be improved and the amount of NOx produced can be reduced. For this reason, according to the invention described in claim 4, in addition to the vibration suppression effect by reducing the generated torque difference as described above, the improvement effect of fuel consumption and exhaust emission can be obtained.

  According to a fifth aspect of the present invention, in the second or third aspect of the invention, the first cylinder group and the second cylinder group are provided, and only the exhaust gas from the cylinders of the first cylinder group is the above-mentioned. The turbocharger is used to drive the supercharger, and air from the supercharger is supplied only to the cylinders of the second cylinder group.

  According to the fifth aspect of the present invention, the cylinders of the second cylinder group are supercharged. Therefore, the air-fuel ratio of the air-fuel mixture is increased to a larger required torque than when supercharging is not performed. Can be operated more leanly, thereby improving fuel efficiency and reducing the amount of NOx produced.

  In particular, in the invention described in claim 5, the exhaust gas from the cylinders of the second cylinder group is not used for driving the supercharger (that is, the exhaust system of the cylinders of the second cylinder group is supercharged). Therefore, the back pressure does not increase in the cylinders of the second cylinder group, so that the exchange of fresh air and burned gas is easily performed, and the amount of burned gas remaining in the cylinder is reduced. Since it can be reduced, the air-fuel ratio of the air-fuel mixture can be made leaner and stable operation can be performed. As a result, the fuel consumption can be further improved and the amount of NOx produced can be reduced as compared with the case where the supercharging is performed for the cylinder in which the exhaust gas is used to drive the supercharger.

  In the invention according to claim 5, the exhaust gas from the cylinders of the first cylinder group is used for driving the supercharger (that is, supercharging the exhaust system of the cylinders of the first cylinder group). Machine is provided). For this reason, the back pressure is increased in the cylinders of the first cylinder group, and therefore, it is easy to ensure the exhaust gas recirculation amount (that is, the in-cylinder residual burned gas amount, so-called internal EGR amount). On the other hand, when operating with the air-fuel ratio of the air-fuel mixture as lean, it is generally possible to reduce the amount of NOx produced by ensuring a sufficient exhaust gas recirculation amount. It becomes particularly large when operating as lean (for example, less than 20) close to the fuel ratio.

  Therefore, according to the fifth aspect of the present invention, when the air-fuel ratio of the air-fuel mixture is operated as lean in the cylinders of the first cylinder group (particularly when operating as lean (for example, less than 20) close to the theoretical air-fuel ratio). ), The amount of NOx generated can be easily reduced as compared with the case where the same operation is performed in a cylinder in which the exhaust gas is not used for driving the supercharger. As a result, this makes it possible to operate with the air-fuel ratio of the air-fuel mixture leaning to a larger required torque, thereby making it possible to improve fuel consumption and reduce NOx generation in a wider operating range. .

  As described above, according to the invention described in claim 5, in addition to the vibration suppression effect by reducing the generated torque difference as described above, it is possible to obtain the improvement effect of the fuel consumption and the exhaust emission.

  According to a sixth aspect of the present invention, in the invention according to any one of the second to fifth aspects, the required torque for the internal combustion engine is equal to or less than a first reference torque that is predetermined according to the engine speed. The air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group not supplied with air from the supercharger is made lean, and the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group supplied with air from the supercharger Is made larger than the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group not supplied with air from the supercharger.

  According to the sixth aspect of the present invention, when the required torque is relatively low, the generated torque of the cylinders in the cylinder group to which the air from the supercharger is supplied and the air from the supercharger The difference from the generated torque of the cylinders in the cylinder group that is not supplied can be reduced, and the occurrence of problems such as vibration can be suppressed. In particular, according to the invention described in claim 6, the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which the air from the supercharger is supplied is further increased, thereby improving fuel consumption and reducing NOx generation amount. To improve exhaust emissions.

  According to a seventh aspect of the invention, in the invention according to any one of the second to sixth aspects, the required torque for the internal combustion engine is greater than a first reference torque that is predetermined according to the engine speed, and When the air pressure is equal to or lower than the second reference torque that is predetermined according to the engine speed and larger than the first reference torque, the air-fuel mixture is empty in the cylinders of the cylinder group not supplied with air from the supercharger. The air-fuel ratio is almost the stoichiometric air-fuel ratio, and the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which the air from the supercharger is supplied is made lean.

  According to the seventh aspect of the present invention, when the required torque is medium, the generated torque of the cylinders in the cylinder group to which the air from the supercharger is supplied and the air from the supercharger are The difference from the generated torque of the cylinders in the cylinder group that is not supplied can be reduced, and the occurrence of problems such as vibration can be suppressed. In addition, combustion and operation are stabilized by setting the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which air from the supercharger is not supplied to substantially the stoichiometric air-fuel ratio. Further, in the invention as set forth in claim 7, the exhaust emission is improved by improving the fuel consumption and reducing the NOx generation amount by increasing the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which the air from the supercharger is supplied. Improvement.

According to an eighth aspect of the present invention, in the invention according to any one of the second to seventh aspects, when the required torque for the internal combustion engine is greater than a second reference torque that is predetermined according to the engine speed. The air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group supplied with air from the supercharger and the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group not supplied with air from the supercharger are both substantially stoichiometric air-fuel ratios. It is supposed to be.
According to the eighth aspect of the invention, the required torque can be realized even when the required torque is relatively high.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the opening / closing timing changing mechanism for changing the opening / closing timing of at least one of the intake valve and the exhaust valve in each cylinder, The cylinder is provided with at least one of a valve lift amount changing mechanism for changing the valve lift amount of at least one of the intake valve and the exhaust valve, and in each of the cylinders, when the air-fuel ratio of the air-fuel mixture is made lean The valve overlap amount of the intake valve and the exhaust valve is increased compared to the case where the air-fuel ratio of the air-fuel mixture is the stoichiometric air-fuel ratio.

  In general, when the air-fuel ratio of the air-fuel mixture is operated as lean (especially when operating as lean (eg, less than 20) close to the stoichiometric air-fuel ratio), a sufficient exhaust gas recirculation amount (in this case, in-cylinder residual burned fuel) The amount of NOx produced can be reduced by securing the so-called internal EGR amount, which is the amount of gas. In general, the exhaust gas recirculation amount can be increased by increasing the valve overlap amount.

  As described above, according to the ninth aspect of the invention, in addition to the vibration suppression effect by reducing the generated torque difference as described above, the exhaust emission improvement effect by reducing the NOx generation amount can also be obtained.

  According to a tenth aspect of the present invention, in the invention according to any one of the first to ninth aspects, the displacement of cylinders in a cylinder group to which air from the supercharger is supplied as the generated torque difference reducing means. Further, the displacement of the cylinders in the cylinder group to which the air from the supercharger is not supplied is increased.

  In general, the torque generated in the cylinder can be increased by increasing the displacement. Therefore, according to the tenth aspect of the present invention, the torque generated in the cylinder group to which the air from the supercharger is supplied and the cylinder group in the cylinder group to which the air from the supercharger is not supplied. The difference from the generated torque can be reduced, and the occurrence of problems such as vibration can be suppressed.

  According to an eleventh aspect of the present invention, in the invention according to any one of the first to tenth aspects, the compression ratio in a cylinder of a cylinder group to which air from the supercharger is supplied as the generated torque difference reducing means. The compression ratio in the cylinders of the cylinder group to which air from the supercharger is not supplied is increased.

  In general, the torque generated in the cylinder can be increased by increasing the compression ratio. Therefore, according to the eleventh aspect of the present invention, the torque generated in the cylinder group to which the air from the supercharger is supplied and the cylinder group in the cylinder group to which the air from the supercharger is not supplied. The difference from the generated torque can be reduced, and the occurrence of problems such as vibration can be suppressed.

  The invention described in each claim has a plurality of cylinder groups, and only the exhaust gas from the cylinders of a part of the plurality of cylinder groups is used to drive the supercharger. Thus, there is provided a common effect of providing a supercharger-equipped internal combustion engine that reduces a difference in generated torque between cylinders between the cylinder groups.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  As described above, for example, for the purpose of quickly raising the temperature of the exhaust gas purification catalyst disposed in the exhaust gas passage, only the exhaust gas from the cylinders of some of the plurality of cylinder groups is used. In an internal combustion engine with a supercharger that is used to drive a supercharger, exhaust gas is discharged from the supercharger in a cylinder of a cylinder group in which the exhaust gas is used to drive the supercharger. Since the back pressure is higher than the cylinders in the cylinder group that is not used for driving, there is a bias in the distribution of air between the cylinder groups, resulting in a difference in the generated torque between the cylinder groups, causing problems such as vibration May end up.

  The present invention is intended to provide an internal combustion engine with a supercharger that reduces the generated torque difference between the cylinder groups, and an internal combustion engine with a supercharger according to an embodiment of the present invention is provided. And a generated torque difference reducing means for reducing a difference between the generated torque of the cylinders of the cylinder group supplied with air from the supercharger and the generated torque of the cylinders of the cylinder group not supplied with air from the supercharger. ing.

  FIG. 1 is an overall configuration diagram for explaining an internal combustion engine with a supercharger according to an embodiment of the present invention. The internal combustion engine in this embodiment is a V-type 6-cylinder gasoline engine with a supercharger. Although a gasoline engine is described here as an example, the present invention is not limited to this, and a diesel engine may be used in another embodiment.

  In FIG. 1, reference numeral 10 denotes an engine body. The engine body 10 includes a first cylinder group 100 including a first cylinder (# 1), a second cylinder (# 2), and a third cylinder (# 3), and a fourth cylinder. (# 4), the second cylinder group 200 including the fifth cylinder (# 5) and the sixth cylinder (# 6). The engine body 10 includes an opening / closing timing changing mechanism 16 for changing the opening / closing timings of the intake valves 121 and 221 and the exhaust valves 122 and 222 of each cylinder, and the intake valves 121 and 221 and the exhaust valves 122 and 222 of each cylinder. A valve lift amount changing mechanism 17 for changing the valve lift amount is provided. Further, the engine body 10 is provided with a coolant temperature sensor 15 for detecting the temperature of the engine coolant.

  As shown in FIG. 1, the intake manifold 101 connected to each cylinder of the first cylinder group 100 is connected to the outlet of the compressor 103a of the supercharger 103 via the intake pipe 102, and is connected to the inlet of the compressor 103a. Is coupled to the air cleaner 104. Between the air cleaner 104 and the compressor 103a, an air flow meter 105 that detects the intake air amount of the cylinders of the first cylinder group 100 is provided. A throttle valve 106 driven by a step motor is disposed in the intake pipe 102, and a cooling device (intercooler) 107 for cooling intake air flowing through the intake pipe 102 is disposed around the intake pipe 102. . In the embodiment shown in FIG. 1, the engine cooling water is guided into the intercooler 107, and the intake air is cooled by the engine cooling water. On the other hand, the exhaust manifold 110 connected to each cylinder of the first cylinder group 100 is connected to the inlet of the exhaust turbine 103b of the supercharger 103, and the outlet of the exhaust turbine 103b is connected to the upstream three-way catalyst via the exhaust pipe 111. 112.

  On the other hand, the intake manifold 201 connected to each cylinder of the second cylinder group 200 is connected to an air cleaner 204 via an intake pipe 202. A throttle valve 206 driven by a step motor is disposed in the intake pipe 202, and an air flow meter 205 for detecting the intake air amount of the cylinders of the second cylinder group 200 is provided between the air cleaner 204 and the throttle valve 206. ing. Further, the exhaust manifold 210 connected to each cylinder of the second cylinder group 200 is connected to the upstream side three-way catalyst 212 via the exhaust pipe 211.

  As shown in FIG. 1, the exhaust pipes 111 and 211 join downstream of the upstream side three-way catalysts 112 and 212 to form a collective exhaust pipe 20, and the collective exhaust pipe 20 is connected to the downstream side three-way catalyst 30. Connected to In the present embodiment, a NOx storage catalyst 40 for removing NOx in the exhaust gas is provided further downstream of the downstream side three-way catalyst 30.

  In the present embodiment, as shown in FIG. 1, air-fuel ratio sensors 113 and 213 for detecting the air-fuel ratio are provided upstream of the upstream side three-way catalysts 112 and 212 (the air-fuel ratio sensor 113 will be described in detail). Are respectively provided upstream of the inlet of the exhaust turbine 103b, and oxygen concentration sensors 114 and 214 for detecting the oxygen concentration are provided downstream of the upstream three-way catalysts 112 and 212, respectively.

  The electronic control unit (ECU) 50 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a known type digital computer in which input / output ports are connected by a bidirectional bus. For controlling the engine speed, the intake air amount, etc., by exchanging signals with various sensors and driving devices including the coolant temperature sensor 15, air flow meters 105 and 205, air-fuel ratio sensors 113 and 213, and oxygen concentration sensors 114 and 214. In addition to obtaining necessary parameters, various controls relating to engine operation such as air-fuel ratio control (fuel injection amount control) and ignition timing control are performed based on the obtained parameters.

  The opening / closing timing changing mechanism 16 and the valve lift amount changing mechanism 17 are also connected to the ECU 50, and the opening / closing timings and valve lift amounts of the intake and exhaust valves are controlled by signals from the ECU 50. The throttle valves 106 and 206 described above are also connected to the ECU 50, and the opening degree of each throttle valve 106 and 206 is controlled by a signal from the ECU 50. In this embodiment, the opening degree of each throttle valve 106 and 206 can be controlled independently.

  As understood from the above description of the configuration, in the internal combustion engine of the present embodiment, only exhaust gas from a cylinder of a part of the plurality of cylinder groups (that is, the cylinders of the first cylinder group 100) is excessive. It is used to drive the feeder 103. Further, the exhaust gas used for driving the supercharger 103 (ie, exhaust gas from the cylinders of the first cylinder group 100) and the exhaust gas not used for driving the supercharger 103 (ie, the second cylinder group). Exhaust gas purification catalysts (downstream three-way catalyst 30, NOx occlusion catalyst 40) are provided in an exhaust gas passage (that is, the collective exhaust pipe 20) through which both of the exhaust gases from 200 cylinders) pass.

  By the way, as described above, the exhaust gas purifying catalyst generally used in the present embodiment has sufficient exhaust gas purifying performance when its temperature is high to some extent, that is, when it is above the so-called activation temperature. It has the property of exhibiting. For this reason, from the viewpoint of improving exhaust emission, it is desirable to maintain the temperature of the exhaust gas purification catalyst at the activation temperature or higher during the operation of the internal combustion engine. In particular, during the cold start, the temperature of the exhaust gas purification catalyst is quickly increased. It is desirable to raise it.

  In this respect, only the exhaust gas from the cylinders of a part of the plurality of cylinder groups (that is, the cylinders of the first cylinder group 100) as in the present embodiment is used to drive the supercharger 103. The exhaust gas used for driving the supercharger 103 (ie, exhaust gas from the cylinders of the first cylinder group 100) and the exhaust gas not used for driving the supercharger 103 ( That is, an exhaust gas purification catalyst (downstream three-way catalyst 30, NOx storage catalyst 40) is provided in an exhaust gas passage (that is, the collective exhaust pipe 20) through which both the exhaust gases from the cylinders of the second cylinder group 200 pass. If so, the temperature of the exhaust gas that has not been used to drive the supercharger 103 (that is, the exhaust gas from the cylinders of the second cylinder group 200) is maintained high. To raise quickly It is possible.

  However, on the other hand, when only exhaust gas from a cylinder of a part of the plurality of cylinder groups is used to drive the supercharger, the exhaust gas is supercharged. Since the exhaust gas in the cylinders of the cylinder group used for driving the engine has a higher back pressure than the cylinders of the cylinder group not used for driving the supercharger, there is a bias in the distribution of air between the cylinder groups. There may be a problem in vibration or the like due to a difference in the generated torque of the cylinders between the groups.

  In this regard, in this embodiment, as shown in FIG. 1, the intake passage is made independent between the cylinders of the first cylinder group 100 and the cylinders of the second cylinder group 200, and the cylinders of the first cylinder group 100 are arranged. And the cylinders of the second cylinder group 200 independently control the intake air amount and the air-fuel ratio of the air-fuel mixture, and the generated torque of the cylinders of the first cylinder group 100 and the cylinders of the second cylinder group 200 The difference from the generated torque is reduced, and the occurrence of problems such as vibration is suppressed.

  That is, the cylinders of the first cylinder group 100 and the cylinders of the second cylinder group 200 control the intake air amount and the air-fuel ratio of the air-fuel mixture independently of each other. The generated torque is controlled independently for each of the cylinders in the two-cylinder group 200 to reduce the generated torque difference. In this embodiment, as a result of the intake passages being made independent between the cylinders of the first cylinder group 100 and the cylinders of the second cylinder group 200, the air from the supercharger 103 is allowed to flow into the first cylinder group 100. It is supplied only to the cylinder.

  Specifically, in the present embodiment, the intake air amount and the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 are the same, and the generated torque of the cylinders of the second cylinder group 200 is the generation of the cylinders of the first cylinder group 100. It is controlled to match the torque. That is, the intake air amount and the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which the air from the supercharger 103 is not supplied (that is, the cylinders of the second cylinder group 200) are not supplied from the supercharger 103. The generated torque of the cylinder group (that is, the cylinder of the second cylinder group 200) matches the generated torque of the cylinder group of the cylinder group to which the air from the supercharger 103 is supplied (that is, the cylinder of the first cylinder group 100). To be controlled. And by doing in this way, the said generated torque difference is reduced and generation | occurrence | production of problems, such as a vibration, is suppressed.

  Specifically, in the present embodiment, the air-fuel ratio of the air-fuel mixture in the cylinders 100 and 200 in the cylinder groups is controlled based on the maps shown in FIGS. 2 and 3 in this embodiment. . That is, the maps shown in FIGS. 2 and 3 appropriately set the air-fuel ratio of the air-fuel mixture in the cylinders 100 and 200 according to the engine operating state specified by the engine speed NE and the required torque Tqr for the internal combustion engine. And is prepared in advance based on experiments and the like.

  First, FIG. 2 will be described. FIG. 2 is a map applied to the cylinders of the first cylinder group 100. The horizontal axis indicates the engine speed NE, and the vertical axis indicates the required torque Tqr for the internal combustion engine. When the engine operating state is in the region indicated by X1 in FIG. 2, that is, the required torque Tqr is a reference torque that is predetermined according to the engine speed NE and is represented by a curve R1 in FIG. In this embodiment, the lean air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group 100 is considerably larger than the stoichiometric air-fuel ratio (for example, a predetermined value of 23 or more). It is controlled to become.

  On the other hand, when the engine operating state is in the region indicated by X2 in FIG. 2, that is, the required torque Tqr is larger than the reference torque represented by the curve R1 in FIG. Accordingly, when the reference torque is predetermined in accordance with the reference torque represented by the curve R2 in FIG. 2, the air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group 100 is almost theoretical in this embodiment. The air-fuel ratio is controlled.

  Next, FIG. 3 will be described. FIG. 3 is a map applied to the cylinders of the second cylinder group 200. As in FIG. 2, the horizontal axis represents the engine speed NE and the vertical axis represents the required torque Tqr for the internal combustion engine. . Curves R1 (dotted lines) and R2 shown in FIG. 3 indicate the same torque values as those in FIG.

  When the engine operating state is in the region indicated by X3 in FIG. 3, that is, the required torque Tqr is a reference torque that is predetermined according to the engine speed NE and is represented by a curve R3 in FIG. In this embodiment, the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 is a lean air-fuel ratio that is relatively close to the stoichiometric air-fuel ratio (for example, a predetermined value less than 20). To be controlled.

  On the other hand, when the engine operating state is in the region indicated by X4 in FIG. 3, that is, the required torque Tqr is larger than the reference torque represented by the curve R3 in FIG. 3 and represented by the curve R2. In the present embodiment, the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 is controlled to be substantially the stoichiometric air-fuel ratio.

  When the required torque Tqr is larger than the reference torque represented by the curve R2 in FIGS. 2 and 3, the fuel increasing operation is performed for the purpose of increasing the output, and the air-fuel mixture is empty in each cylinder. The fuel ratio is rich. Also, when the fuel increase operation is performed for the purpose of lowering the catalyst temperature, the air-fuel ratio of the air-fuel mixture in each cylinder is made rich.

  Further, in the map shown in FIG. 2, the air-fuel ratio of the air-fuel mixture is made leaner (that is, with a larger lean air-fuel ratio) up to a larger required torque Tqr (that is, in a wider operating range) than the map shown in FIG. ) The operation is possible because the cylinders of the first cylinder group 100 are supercharged. In addition, since the air-fuel ratio of the air-fuel mixture can be made leaner to a higher required torque Tqr in this way, fuel consumption can be improved and the amount of NOx generated can be reduced.

  Further, as can be understood from the description of FIG. 2 and FIG. 3 described above, in the present embodiment, when the required torque Tqr for the internal combustion engine is equal to or less than the reference torque represented by the curve R3 in FIG. The air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 is lean, and the air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group 100 is greater than the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200. Is also getting bigger.

  In this way, when the required torque Tqr is relatively low, the difference between the generated torque of the cylinders of the first cylinder group 100 and the generated torque of the cylinders of the second cylinder group 200 can be reduced. The occurrence of problems such as vibration can be suppressed. In particular, in this case, the air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group 100, which is the cylinder group to which the air from the supercharger 103 is supplied, is increased to improve fuel consumption and generate NOx. It is possible to improve exhaust emissions by reducing the amount.

  Further, as can be understood from the description of FIG. 2 and FIG. 3 described above, in the present embodiment, the required torque Tqr for the internal combustion engine is larger than the reference torque represented by the curve R3 in FIG. When it is equal to or lower than the reference torque represented by R1, the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 is substantially the stoichiometric air-fuel ratio, and the air-fuel mixture in the cylinders of the first cylinder group 100 is The air-fuel ratio is made lean.

  In this way, when the required torque Tqr is medium, the difference between the generated torque of the cylinders of the first cylinder group 100 and the generated torque of the cylinders of the second cylinder group 200 can be reduced. The occurrence of problems such as vibration can be suppressed. Further, the combustion and operation can be stabilized by setting the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200, which is a cylinder group not supplied with air from the supercharger 103, to a substantially stoichiometric air-fuel ratio. . Further, by increasing the air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group, which is the cylinder group supplied with air from the supercharger 103, the exhaust emission is improved by improving the fuel consumption and reducing the NOx generation amount. Can be planned.

  Further, as can be understood from the description of FIGS. 2 and 3 described above, in the present embodiment, the required torque Tqr for the internal combustion engine is larger than the reference torque represented by the curve R1 and represented by the curve R2. When the reference torque is less than or equal to the reference torque, the air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group 100 and the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 are both substantially the stoichiometric air-fuel ratio. It has become so. In this way, even when the required torque Tqr is relatively high, the required torque can be realized.

  In this embodiment, the engine operating state is in the region indicated by X3 in FIG. 3, and the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 is relatively close to the stoichiometric air-fuel ratio (for example, 20 When the operation is performed with the air-fuel ratio of the air-fuel mixture being the stoichiometric air-fuel ratio, the valve overlap amount of the intake valve 221 and the exhaust valve 222 in the cylinders of the second cylinder group 200 is operated. It is to be increased more than the case. The increase in the valve overlap amount is realized by operating at least one of the opening / closing timing changing mechanism 16 and the valve lift amount changing mechanism 17.

  In general, when operating with the air-fuel ratio of the air-fuel mixture as lean, the amount of NOx produced can be reduced by ensuring a sufficient exhaust gas recirculation amount (in this case, the amount of residual burned gas in the cylinder, the so-called internal EGR amount). The effect is particularly great when the air-fuel ratio of the air-fuel mixture is operated as lean (for example, less than 20) close to the stoichiometric air-fuel ratio. In general, the exhaust gas recirculation amount can be increased by increasing the valve overlap amount. For this reason, it is possible to obtain an exhaust emission improvement effect by further reducing the NOx generation amount by increasing the valve overlap amount as described above. In another embodiment, when the air-fuel ratio of the air-fuel mixture is made lean in each of the first and second cylinder groups 100 and 200, the valve overlap amount is equal to the stoichiometric air-fuel ratio. It may be increased more than the case where it is done.

  Also, here, the opening / closing timing changing mechanism 16 for changing the opening / closing timing of the intake valves 121, 221 and the exhaust valves 122, 222 of each cylinder, and the valve lift of the intake valves 121, 221 and the exhaust valves 122, 222 of each cylinder. Although an example in which the valve lift amount changing mechanism 17 for changing the amount is provided has been described, in order to increase the valve overlap amount, the intake valves 121 and 221 and the exhaust gas are exhausted in each cylinder. An opening / closing timing changing mechanism for changing the opening / closing timing of at least one of the valves 122, 222, and a valve lift amount changing mechanism for changing the valve lift amount of at least one of the intake valves 121, 221 and the exhaust valves 122, 222 in each cylinder. It is sufficient that at least one of the above is provided.

  As described above, according to the supercharger-equipped internal combustion engine of the present embodiment, the temperature of the exhaust gas purifying catalyst arranged in the exhaust gas passage can be quickly raised at the time of cold start, and In addition, it is possible to suppress the occurrence of problems such as vibration by reducing the generated torque difference between the cylinder groups. Further, by operating with the air-fuel ratio of the air-fuel mixture lean, it is possible to improve fuel consumption and improve exhaust emission by reducing the amount of NOx generated.

  Hereinafter, other embodiments of the present invention will be described. In addition, each embodiment described below has many common parts in the configuration and operational effects of the above-described embodiments, and description of these common parts is omitted in principle.

  First, the embodiment shown in FIG. 4 will be described. FIG. 4 is an overall configuration diagram for explaining an internal combustion engine with a supercharger according to this embodiment. As apparent from FIG. 4, the configuration of the present embodiment is almost the same as the configuration of the above-described embodiment (FIG. 1), but the air from the supercharger 103 is supplied only to the cylinders of the second cylinder group 200. This is different from the configuration of the embodiment described above. That is, in the above-described embodiment, only the exhaust gas from the cylinders of the first cylinder group 100 is used to drive the supercharger 103, and the air from the supercharger 103 is used as the first cylinder group 100. In this embodiment, only the exhaust gas from the cylinders of the first cylinder group 100 is used to drive the supercharger 103 and is supercharged. Air from the machine 103 is supplied only to the cylinders of the second cylinder group 200. Note that the configuration of the present embodiment can also quickly raise the temperature of the exhaust gas purification catalyst disposed in the exhaust gas passage, as in the case of the above-described embodiment.

  Also in this embodiment, as in the case of the above-described embodiment, the cylinders of the first cylinder group 100 and the cylinders of the second cylinder group 200 are independent of the intake passage and the cylinders of the first cylinder group 100 and the above-described cylinders. The intake air amount and the air-fuel ratio of the air-fuel mixture are controlled independently by the cylinders of the second cylinder group 200, and the generated torque of the cylinders of the first cylinder group 100 and the generated torque of the cylinders of the second cylinder group 200 are controlled. And the occurrence of problems such as vibration are suppressed.

  In the present embodiment, during normal operation, the air-fuel ratio of the air-fuel mixture in the cylinders 100 and 200 is controlled based on the maps shown in FIGS. Similar to the maps shown in FIGS. 2 and 3 described above, the maps shown in FIGS. 5 and 6 correspond to the engine operating state specified by the engine speed NE and the required torque Tqr for the internal combustion engine. This is for appropriately determining the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder groups 100 and 200, and is created in advance based on experiments and the like.

  First, FIG. 5 will be described. FIG. 5 is a map applied to the cylinders of the second cylinder group 200, which is a cylinder group supplied with air from the supercharger 103. The horizontal axis represents the engine speed NE, and the vertical axis represents the internal combustion engine. The required torque Tqr for the engine is shown. When the engine operating state is in the region indicated by Y1 in FIG. 5, that is, the required torque Tqr is a reference torque that is predetermined according to the engine speed NE and is represented by a curve K1 in FIG. In this embodiment, the lean air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 is considerably larger than the stoichiometric air-fuel ratio (for example, a predetermined value of 23 or more). It is controlled to become.

  On the other hand, when the engine operating state is in the region indicated by Y2 in FIG. 5, that is, the required torque Tqr is larger than the reference torque represented by the curve K1 in FIG. Accordingly, when the reference torque is predetermined in accordance with the reference torque represented by the curve K2 in FIG. 5, the air-fuel ratio of the air-fuel mixture in the cylinders of the second cylinder group 200 is almost theoretical in this embodiment. The air-fuel ratio is controlled.

  Next, FIG. 6 will be described. FIG. 6 is a map applied to the cylinders of the first cylinder group 100, which is a cylinder group to which air from the supercharger 103 is not supplied. As in FIG. 5, the horizontal axis represents the engine speed NE. The vertical axis represents the required torque Tqr for the internal combustion engine. Curves K1 (dotted lines) and K2 shown in FIG. 6 indicate the same torque values as those in FIG.

  When the engine operating state is in the region indicated by Y3 in FIG. 6, that is, the required torque Tqr is a reference torque that is predetermined according to the engine speed NE and is represented by a curve K3 in FIG. In this embodiment, the air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group 100 is a lean air-fuel ratio that is relatively close to the stoichiometric air-fuel ratio (for example, a predetermined value less than 20). To be controlled.

  On the other hand, when the engine operating state is in the region indicated by Y4 in FIG. 6, that is, the required torque Tqr is greater than the reference torque represented by the curve K3 in FIG. 6 and is represented by the curve K2. In the present embodiment, the air-fuel ratio of the air-fuel mixture in the cylinders of the first cylinder group 100 is controlled to be substantially the stoichiometric air-fuel ratio.

  As in the case of the above-described embodiment, also in this embodiment, when the required torque Tqr is larger than the reference torque represented by the curve K2 in FIGS. 5 and 6, the purpose is to increase the output. Fuel increase operation is performed, and the air-fuel ratio of the air-fuel mixture in each cylinder is made rich. Also, when the fuel increase operation is performed for the purpose of lowering the catalyst temperature, the air-fuel ratio of the air-fuel mixture in each cylinder is made rich.

  Further, in the map shown in FIG. 5, the air-fuel ratio of the air-fuel mixture is made leaner (that is, with a larger lean air-fuel ratio) than the map shown in FIG. 6 up to a larger required torque Tqr (that is, in a wider operating region). The reason why the engine can be operated is that supercharging is performed on the cylinders of the second cylinder group 200. In addition, since the air-fuel ratio of the air-fuel mixture can be made leaner to a higher required torque Tqr in this way, fuel consumption can be improved and the amount of NOx generated can be reduced.

  In particular, in this embodiment, the exhaust gas from the cylinders of the second cylinder group 200 is not used for driving the supercharger 103 (that is, a supercharger is provided in the exhaust system of the cylinders of the second cylinder group 200). Therefore, the back pressure does not increase in the cylinders of the second cylinder group 200, and therefore, the exchange of fresh air and burned gas can be easily performed, and the amount of burnt residual burned gas can be reduced. In addition, the air-fuel ratio of the air-fuel mixture can be made leaner and stable operation can be performed. As a result, for example, as in the case of the above-described embodiment, the fuel consumption can be further improved and the fuel consumption can be improved as compared with the case where the supercharging is performed for the cylinder in which the exhaust gas is used for driving the supercharger. The production amount can be reduced.

  In the present embodiment, the exhaust gas from the cylinders of the first cylinder group 100 is used to drive the supercharger 103 (that is, the supercharger 103 is connected to the exhaust system of the cylinders of the first cylinder group 100). Provided). For this reason, the back pressure increases in the cylinders of the first cylinder group 100, and therefore, it becomes easy to ensure the exhaust gas recirculation amount (that is, the in-cylinder residual burned gas amount, so-called internal EGR amount). That is, the exhaust gas recirculation amount can be easily increased by increasing the valve overlap amount.

  As described above, when the air-fuel ratio of the air-fuel mixture is operated as lean, it is generally possible to reduce the amount of NOx produced by ensuring a sufficient exhaust gas recirculation amount. Is particularly large when the engine is operated as lean (for example, less than 20) close to the theoretical air-fuel ratio.

  Therefore, according to this embodiment, when the air-fuel ratio of the air-fuel mixture is operated lean in the cylinders of the first cylinder group 100 (that is, the air-fuel mixture is in the region indicated by Y3 in FIG. 6). Cylinders in which the exhaust gas is not used for driving the supercharger, such as the cylinders of the second cylinder group 200 of the above-described embodiment, for example, when the air-fuel ratio of the engine is operated as lean (for example, less than 20) close to the stoichiometric air-fuel ratio. Therefore, the amount of NOx produced can be easily reduced as compared with the case where the same operation is performed. As a result, it is possible to operate with the air-fuel ratio of the air-fuel mixture leaning to a larger required torque Tqr, thereby improving fuel consumption and reducing NOx generation in a wider operating range. Become.

  In addition, since it seems to be clear from the description so far, in the present embodiment, detailed description of the air-fuel ratio control for each degree of the required torque Tqr and the effect thereof as performed in the previous embodiment is omitted. However, also in the present embodiment, the torque generated by the cylinders of the first cylinder group 100 is controlled by controlling the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder groups 100 and 200 based on the maps shown in FIGS. And the occurrence of problems such as vibrations can be suppressed by reducing the difference between the torque generated by the cylinders of the second cylinder group 200 and improvement of exhaust emission by reducing NOx generation amount. Can do.

  Next, still another embodiment of the present invention will be described. In this embodiment, as a means for reducing the difference in generated torque between the cylinder groups, a cylinder group in which air from the supercharger is not supplied than the displacement of the cylinders in the cylinder group to which air from the supercharger is supplied. The displacement of the cylinder is increased.

  That is, in the configuration of this embodiment, for example, in the configuration shown in FIG. 1, the supercharger is more than the displacement of the cylinders of the first cylinder group 100 that is the cylinder group to which the air from the supercharger 103 is supplied. The displacement of the cylinders of the second cylinder group 200, which is the cylinder group to which air from 103 is not supplied, is increased.

  Alternatively, in the configuration shown in FIG. 4, a cylinder in which air from the supercharger 103 is not supplied than the displacement of the cylinders in the second cylinder group 200, which is a cylinder group to which air from the supercharger 103 is supplied. The displacement of the cylinders of the first cylinder group 100, which is a group, may be increased.

  Here, the reason why the displacement of the cylinders in the cylinder group to which the air from the supercharger 103 is not supplied is larger than the displacement of the cylinders in the cylinder group to which the air from the turbocharger is supplied is, for example, This is performed by at least one of increasing the cylinder bore diameter and lengthening the piston stroke in the cylinders of the cylinder group not supplied with air from the machine 103 than in the cylinders of the cylinder group supplied with air from the supercharger 103.

  In general, the generated torque of the cylinder can be increased by increasing the displacement, so that the generation of the cylinders in the cylinder group to which the air from the supercharger is supplied can be achieved as in the present embodiment. The difference between the torque and the generated torque of the cylinders in the cylinder group to which air from the supercharger is not supplied can be reduced, and the occurrence of problems such as vibration can be suppressed.

  Next, still another embodiment of the present invention will be described. In this embodiment, as a means for reducing the difference in generated torque between the cylinder groups, a cylinder group in which air from the supercharger is not supplied than a compression ratio in a cylinder of the cylinder group to which air from the supercharger is supplied. The compression ratio in the cylinder is increased.

  That is, in the configuration of this embodiment, for example, in the configuration shown in FIG. 1, the supercharger is more than the compression ratio in the cylinders of the first cylinder group 100 that is a cylinder group to which air from the supercharger 103 is supplied. The compression ratio in the cylinders of the second cylinder group 200, which is a cylinder group to which air from 103 is not supplied, is increased.

  Alternatively, in the configuration shown in FIG. 4, a cylinder to which air from the supercharger 103 is not supplied than a compression ratio in a cylinder of the second cylinder group 200 that is a cylinder group to which air from the supercharger 103 is supplied. The compression ratio in the cylinders of the first cylinder group 100 that is a group may be increased.

  Here, the reason why the compression ratio is different between the cylinders of the cylinder group to which air from the supercharger 103 is not supplied and the cylinders of the cylinder group to which air from the supercharger 103 is supplied is, for example, The cylinder bore diameter, piston stroke, intake / exhaust valve opening / closing timing, etc. are made different between the cylinders in the cylinder group to which no air is supplied and the cylinders in the cylinder group to which the air from the supercharger 103 is supplied.

  In general, by increasing the compression ratio, the generated torque of the cylinder can be increased. Therefore, by performing the present embodiment, the cylinders of the cylinder group to which the air from the supercharger 103 is supplied are provided. The difference between the generated torque and the generated torque of the cylinders in the cylinder group to which air from the supercharger 103 is not supplied can be reduced, and the occurrence of problems such as vibration can be suppressed.

  Further, for the purpose of rapidly increasing the temperature of the exhaust gas purification catalyst disposed in the exhaust gas passage, only the exhaust gas from the cylinders of some of the plurality of cylinder groups is used as a supercharger. As a further configuration of an internal combustion engine with a supercharger that is used for driving, the internal combustion engine with a supercharger is configured to reduce a difference in torque generated between cylinders between cylinder groups. The configuration shown in FIG. 7 can be considered.

  As shown in FIG. 7, in this internal combustion engine, the intake air passage and the exhaust gas to the cylinder (that is, the cylinders of the first cylinder group 100) in which the exhaust gas is used to drive the supercharger 103 are the above-mentioned excess gas. The intake air passage to the cylinders that are not used for driving the charger 103 (that is, the cylinders of the second cylinder group 200) is common to the upstream of the throttle valves 106 and 206, and the air from the supercharger 103 is exhaust gas. Are used for both cylinders used for driving the supercharger 103 (that is, cylinders of the first cylinder group 100) and cylinders where exhaust gas is not used for driving the supercharger 103 (that is, cylinders of the second cylinder group 200). It comes to be supplied. In FIG. 7, 302 is an intake pipe, 304 is an air cleaner, 305 is an air flow meter, and 307 is a cooling device (intercooler).

  In such a configuration, the intake air amount and the air-fuel ratio of the air-fuel mixture are controlled independently by the cylinders of the first cylinder group 100 and the cylinders of the second cylinder group 200, respectively. The difference between the generated torque of the cylinders in the cylinder group 100 and the generated torque of the cylinders in the second cylinder group 200 can be reduced, and the occurrence of problems such as vibration can be suppressed.

  In addition, although some specific embodiment was demonstrated above, this invention is not limited to these, For example, it may be made to combine the characteristic of each embodiment mentioned above suitably in other embodiment. Good. Further, here, the case of having two cylinder groups has been described as an example, but other embodiments may have more cylinder groups.

FIG. 1 is an overall configuration diagram for explaining an internal combustion engine with a supercharger according to an embodiment of the present invention. FIG. 2 is a map for determining the air-fuel ratio of the air-fuel mixture applied to the cylinders of the first cylinder group, which is the cylinder group to which air from the supercharger is supplied in the configuration shown in FIG. . FIG. 3 is a map for determining the air-fuel ratio of the air-fuel mixture applied to the cylinders of the second cylinder group, which is the cylinder group to which air from the supercharger is not supplied in the configuration shown in FIG. FIG. 4 is an overall configuration diagram for explaining an internal combustion engine with a supercharger according to another embodiment of the present invention. FIG. 5 is a map for determining the air-fuel ratio of the air-fuel mixture applied to the cylinders of the second cylinder group, which is the cylinder group to which air from the supercharger is supplied in the configuration shown in FIG. . FIG. 6 is a map for determining the air-fuel ratio of the air-fuel mixture applied to the cylinders of the first cylinder group, which is the cylinder group to which air from the supercharger is not supplied in the configuration shown in FIG. FIG. 7 shows an internal combustion engine with a supercharger in which only exhaust gas from the cylinders of a part of the cylinder groups is used to drive the supercharger. It is a figure which shows another structure of the internal combustion engine with a supercharger made to reduce the generated torque difference.

Explanation of symbols

10 Engine Body 30 Three-way Catalyst Downstream 50 Electronic Control Unit (ECU)
100 First cylinder group 103 Supercharger 200 Second cylinder group

Claims (11)

A turbocharged internal combustion engine having a plurality of cylinder groups, wherein only exhaust gas from cylinders of a part of the plurality of cylinder groups is used to drive the turbocharger In the institution
The air from the supercharger is supplied only to the cylinders of the partial cylinder group or only to the cylinders of the cylinder groups other than the partial cylinder group. A turbocharging system comprising: a generated torque difference reducing means for reducing a difference between a generated torque of a cylinder of a cylinder group supplied with air and a generated torque of a cylinder of a cylinder group not supplied with air from the supercharger. Internal combustion engine with a machine.   The generated torque difference reducing means is configured to reduce the intake air amount and the air-fuel mixture independently for each cylinder in the cylinder group to which air from the supercharger is supplied and for each cylinder in the cylinder group to which air from the supercharger is not supplied. 2. The supercharged internal combustion engine according to claim 1, further comprising means for controlling the air-fuel ratio.   The intake air amount and the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group not supplied with air from the supercharger are the same as the generated torque of the cylinders in the cylinder group not supplied with air from the supercharger. The internal combustion engine with a supercharger according to claim 2, wherein the internal combustion engine is controlled so as to coincide with a generated torque of a cylinder of a cylinder group to which air is supplied.   An exhaust gas having a first cylinder group and a second cylinder group, and only exhaust gas from the cylinders of the first cylinder group is used to drive the supercharger and air from the supercharger The internal combustion engine with a supercharger according to claim 2 or 3, characterized in that is supplied only to the cylinders of the first cylinder group.   An exhaust gas having a first cylinder group and a second cylinder group, and only exhaust gas from the cylinders of the first cylinder group is used to drive the supercharger and air from the supercharger The internal combustion engine with a supercharger according to claim 2 or 3, wherein is supplied only to the cylinders of the second cylinder group.   When the required torque for the internal combustion engine is equal to or lower than a first reference torque determined in advance according to the engine speed, the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group not supplied with air from the supercharger is lean. And the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group supplied with air from the supercharger is larger than the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group not supplied with air from the supercharger. An internal combustion engine with a supercharger according to any one of claims 2 to 5, wherein   A second reference torque in which the required torque for the internal combustion engine is greater than a first reference torque that is predetermined according to the engine speed and is greater than the first reference torque that is predetermined according to the engine speed. In the following cases, the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which air from the supercharger is not supplied is substantially the stoichiometric air-fuel ratio, and the cylinder group to which air from the supercharger is supplied The supercharged internal combustion engine according to any one of claims 2 to 6, wherein the air-fuel ratio of the air-fuel mixture in the cylinder is lean.   When the required torque for the internal combustion engine is greater than a second reference torque that is predetermined according to the engine speed, the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group to which the air from the supercharger is supplied and The supercharging according to any one of claims 2 to 7, wherein the air-fuel ratio of the air-fuel mixture in the cylinders of the cylinder group not supplied with air from the supercharger is substantially the stoichiometric air-fuel ratio. Internal combustion engine with a machine. An opening / closing timing changing mechanism for changing the opening / closing timing of at least one of the intake valve and the exhaust valve in each cylinder, and a valve lift amount changing mechanism for changing the valve lift amount of at least one of the intake valve and the exhaust valve in each cylinder. At least one of them,
In each of the above cylinders, when the air-fuel ratio of the air-fuel mixture is made lean, the valve overlap amount between the intake valve and the exhaust valve is increased more than when the air-fuel ratio of the air-fuel mixture is made the stoichiometric air-fuel ratio. The supercharged internal combustion engine according to any one of claims 1 to 8, characterized in that it is characterized in that   As the generated torque difference reducing means, the exhaust amount of the cylinders of the cylinder group not supplied with air from the supercharger is made larger than the exhaust amount of the cylinders of the cylinder group supplied with air from the supercharger. An internal combustion engine with a supercharger according to any one of claims 1 to 9.   As the generated torque difference reducing means, the compression ratio in the cylinders of the cylinder group not supplied with air from the supercharger is made higher than the compression ratio in the cylinders of the cylinder group supplied with air from the supercharger. An internal combustion engine with a supercharger according to any one of claims 1 to 10.

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