JP2010180708A - Turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor assist turbocharger capable of restraining overshoot of an engine speed as well, while shortening a turbo-lag in acceleration or deceleration. <P>SOLUTION: A turbocharger 1, in one example, has an intake turbine 200 and an exhaust compressor 400, and drives the intake turbine 200 by intake negative pressure of an engine 8. Thus, the exhaust compressor 400 reduces exhaust pressure of the engine 8, and can increase torque of the engine 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a turbocharger installed in a vehicle engine.

The throttle valve that adjusts the output of the Otto cycle internal combustion engine has a problem of increasing the pumping loss. The turbocharger may be able to reduce the pumping loss by substituting part or all of the output control function of the throttle valve, and may be able to generate the required torque with a small and light engine. However, in the main control of the vehicle engine by the turbocharger (TC), the turbo lag of the turbocharger becomes a practical problem.
The present invention has been made in view of the above problems, and an object thereof is to provide a TC capable of shortening the turbo lag.
An engine having an EGR device that cools exhaust gas and returns it to the intake pipe of the engine for purifying exhaust gas and improving thermal efficiency is also known. By using the EGR device, it is possible to suppress a decrease in turbine flow rate when the turbocharger is at a low output. However, the EGR cooler for cooling the EGR gas has a problem that the cooling system is complicated and the apparatus weight is increased.

  In order to improve this problem, Patent Document 1 below inputs part of engine exhaust gas to a vortex tube (VT), returns high-temperature exhaust gas discharged from VT to the exhaust system, and is discharged from VT. An EGR device that introduces low-temperature exhaust gas into an intake system through an EGR valve is proposed. That is, the VT of this EGR device constitutes an EGR cooler. However, in this EGR device, only a part of the exhaust gas of the engine is introduced into the VT, so that the exhaust gas cooling effect of the VT is reduced when the flow rate of the exhaust gas discharged from the engine is small. there were. The present invention has been made in view of the above problems, and an object thereof is to provide a TC capable of improving the cooling performance of EGR gas.

Patent Document 2 proposes a motor-assisted turbocharger (MATC) having a magnet field type synchronous motor (PM) in which a permanent magnet is fixed to the back surface of a compressor wheel. However, the compressor wheel must have a much higher centrifugal force resistance than a compressor wheel without a permanent magnet in order to support the centrifugal force of the permanent magnet, so the inertial rotating mass of the compressor wheel itself increases. However, the turbo lag increases. Furthermore, this PM type MATC has a difficult problem of supporting the centrifugal force of the permanent magnet and cooling the permanent magnet. When the engine suddenly stops from a high rotation state, heat is transferred from the high-temperature turbine or turbine casing to the permanent magnet through the rotary shaft or the compressor wheel of the compressor, and the high-temperature demagnetization problem of the permanent magnet becomes serious. It is also conceivable to configure an MATC assist motor by a saddle type induction motor (IM). However, a saddle-type IM rotor requires a saddle-shaped coil through which a secondary current flows in addition to a rotor core that allows magnetic flux to pass through and a robust rotor core that supports the saddle-shaped coil. Will increase. That is, it is a good idea to shorten the turbo lug by torque assist by the motor, but it is very important to reduce the rotor weight of the motor.
An object of the present invention is to reduce a motor-assisted turbocharger excellent in turbo lag shortening performance.

  Furthermore, although the conventional MATC reduces the acceleration delay by shortening the turbo lag by torque assist by the assist motor, after the TC rotation speed increases to the required value, it exceeds the above required value due to the inertial rotation mass of the TC rotor. There was a possibility that the engine output and the rotational speed would be excessive by that amount. The present invention has been made in view of the above problems, and an object of the present invention is to provide a MATC capable of suppressing the overshoot of the engine speed while shortening the turbo lag during acceleration or deceleration.

JP 2002-70657 A WO98 / 02652

In order to achieve the above object, three independent inventions with respect to the turbocharger are described below.
The TC of each invention transfers torque to and from the exhaust side impeller that transfers torque and exhaust gas flowing from the exhaust pipe of the internal combustion engine mounted on the vehicle, and intake air that flows into the internal combustion engine from the intake path for intake of outside air. An intake-side impeller, and the two impellers are connected by a rotating shaft that is rotatably supported by a housing.

A turbocharger according to a first aspect of the present invention has a nozzle for restricting intake air flowing into the intake side impeller, and the intake side impeller is driven by the intake negative pressure of the internal combustion engine to drive the exhaust side impeller. The exhaust gas emitted from the internal combustion engine is pressurized. When the target value of the intake flow rate to the internal combustion engine is large, the throttle amount adjustment mechanism that changes the cross-sectional area of the nozzle passage reduces the nozzle throttle amount, and the target value of the intake flow rate to the internal combustion engine is small. You may increase the aperture amount of a nozzle.
In a preferred embodiment, the apparatus includes a bypass valve that is provided in a bypass pipe that bypasses the intake-side impeller and flows the intake air into the internal combustion engine, and that controls a flow rate of the bypass pipe; and a controller that controls the bypass valve. The controller opens the bypass valve during acceleration of the internal combustion engine.

In a preferred aspect, the controller calculates an error between a target intake air amount of the internal combustion engine and the intake air amount passing through the intake side impeller, and adjusts the opening of the bypass valve in a direction to eliminate the error. .
A turbocharger according to a second aspect of the present invention includes an inlet through which the exhaust gas flows from an exhaust pipe of the internal combustion engine, a low temperature exhaust outlet for sending low temperature exhaust gas to the intake pipe, and a high temperature exhaust outlet for discharging swirling high temperature gas. The high-temperature exhaust outlet of the vortex tube communicates with an exhaust path upstream of the exhaust side impeller.

That is, the entire amount of exhaust gas that has exited from the exhaust pipe of the engine is introduced into the VT. The velocity energy of the high-speed and high-temperature exhaust gas coming out from the high-temperature side outlet of the vortex tube is recovered by the turbocharger exhaust turbine. The low temperature exhaust gas emitted from the low temperature side outlet of the VT is introduced into the intake pipe of the engine. The VT cold exhaust gas may be introduced directly into the intake pipe of the engine or may be introduced upstream of the TC compressor. That is, the low temperature exhaust gas discharged from the VT becomes so-called EGR gas.
Eventually, the VT also serves as a part or all of the function of the turbine inlet nozzle, so that the energy loss of the VT can be minimized. Further, since particulates such as diesel particulates contained in the exhaust gas can be guided to the turbine side by centrifugal force, an EGR valve provided in a gas passage that is circulated from the VT to the intake pipe side of the engine or the intake air of the engine It is possible to satisfactorily prevent carbon from being deposited on the valve and to satisfactorily inhibit carbon from adhering to the inside of the cylinder.

In a preferred aspect, the rotation direction of the exhaust gas in the VT is the same as the rotation direction of the turbine. Thereby, the exhaust gas pipeline structure between the VT and the turbine can be simplified.
A turbocharger according to a third aspect of the present invention is disposed in an exhaust path upstream of the exhaust side impeller and adiabatically expands the exhaust gas to a level lower than an outlet pressure of the intake side impeller and exits from the intake side impeller. It is characterized by having an ejector that sucks pressurized intake air and sends it to the exhaust-side impeller.
That is, in the present invention, the exhaust gas of the engine is adiabatically expanded by the ejector and then flows into the exhaust turbine. Preferably, the ejector is disposed in the vicinity of the inlet of the exhaust turbine, and high-speed exhaust gas emitted from the ejector collides with a blade portion of the exhaust turbine to drive the exhaust turbine. Thereby, the energy loss of exhaust gas can be reduced. In addition, the high-speed exhaust gas flow emitted from the ejector may be compressed by the diff user and flow into the exhaust turbine. Pressurized intake air discharged from the intake compressor is introduced into the ejector, sucked by the high-speed exhaust gas flow in the ejector, and sent to the exhaust turbine. As a result, even if the engine speed is low and the flow rate is small, the flow rates of the intake compressor (intake side impeller) and the exhaust turbine (exhaust side impeller) can be maintained high, and a decrease in TC efficiency can be prevented.

  In a preferred aspect, the apparatus has a bypass valve that is disposed in a bypass pipe that sends the pressurized intake air from the intake side impeller to the ejector and adjusts the flow rate of the pressurized intake air. According to this aspect, the flow rate of the pressurized intake air sent to the ejector can be adjusted by opening and closing the bypass valve. For example, when the engine speed and output are large and the flow rate is large, the bypass valve is closed. Even when the bypass valve is closed, a large flow of pressurized intake air that has exited the compressor can be absorbed by the engine, and a large flow of exhaust gas that has exited the engine can be absorbed by the turbine. When the engine speed and output are small and the flow rate is small, the bypass valve is opened. As a result, only a part of the large flow rate of pressurized intake air from the compressor is sent to the engine, and the remaining pressurized intake air is absorbed by the ejector and sent to the turbine. The compressor energy given to the pressurized intake air sent to the ejector is recovered by the turbine. Thereby, it is possible to satisfactorily prevent an increase in TC loss during engine low-power operation. Of course, an assist motor may be connected to the TC.

In a preferred aspect, the ejector includes an annular passage that is disposed on a radially outer side of the exhaust side impeller so that the exhaust gas flows in an annular shape, and one of the exhaust gas and the pressurized intake air has an axial direction and a diameter. The other of the exhaust gas and the pressurized intake air flows in the other of the axial direction and the radial direction and flows into the annular passage. In this case, the annular passage that forms the high-speed annular exhaust gas flow flowing into the turbine also serves as the ejector, so that fluid loss can be reduced and the structure can be simplified.
In a preferred aspect, the rotor includes an assist motor that has a rotor coupled to the rotating shaft and transmits and receives torque to and from the intake-side impeller and the exhaust-side impeller, and the assist motor is configured by a switched reluctance motor (SRM). ing.

  According to the motor-assisted turbocharger (MATC) of the present invention, since the inertial rotation mass of the rotor can be reduced, the turbo lag and the rotation speed overshoot after the turbo lag can be significantly shortened. As a result, it is possible to reduce the size and weight of the engine while ensuring the necessary vehicle acceleration performance. More specifically, since the SRM can be constituted only by the rotor core for flowing the magnetic flux φ, it does not require a permanent magnet, a support member for supporting it, or a saddle coil conductor. As a result, this SRM type assist motor can significantly reduce the rotor's inertial rotating mass as compared with a conventional assist motor constituted by a permanent magnet synchronous motor (PM) or a saddle type induction motor (IM). . The above-mentioned advantages by adopting RM as an MATC assist motor have not been recognized in the past.

  In a preferred embodiment, the rotor has a rotor connected to the rotating shaft, and has an assist motor that transmits and receives torque to and from the intake-side impeller and the exhaust-side impeller, and the assist motor includes the disk-shaped rotor and the rotor An axial gap structure having a front side stator facing the front end surface with a small gap in the axial direction and a back side stator facing the rear end surface of the rotor with a small gap in the axial direction; Magnetic poles of the same phase in the stator and the back side stator are arranged at substantially the same circumferential position to generate substantially the same amount of magnetic flux, and the rotor has a circumferential magnetic field that is less than half of the axial magnetic path cross-sectional area. A rotor core having a road cross-sectional area; Here, “substantially the same circumferential position” means that the amount of deviation in the circumferential direction between the front side stator coil and the back side stator coil having the same current phase is an electrical angle of π / 12 or less. Means that. Further, “substantially the same amount of magnetic flux” means that the difference in the amount of magnetic flux is less than 15%.

  That is, according to the present invention, a motor having an axial gap structure (including an oblique gap structure described later) having a structure in which magnetic flux flows in the rotor core substantially in the axial direction and hardly flows in the circumferential direction in the rotor core is used as an assist motor for the MATC. Has its characteristics. The rotor core structure in which the magnetic flux in the rotor core flows almost in the axial direction is realized by flowing the same spatial phase stator current through a pair of stator coils provided on both sides of the rotor core in the axial direction. In this way, the rotor core requires substantially no yoke (magnetic path member) for flowing magnetic flux in the circumferential direction, and thus can be significantly reduced in weight. As a result, an increase in the inertial rotation mass of the MATC due to the addition of the assist motor can be suppressed, so that the turbo lag can be greatly reduced, and the boost pressure of the TC and the reduction in size and weight of the engine can be reduced accordingly. Can be promoted.

  Further, the AXM having a stator on both sides in the axial direction of the rotor can greatly increase the electromagnetic gap area between the stator and the rotor as compared with a radial gap motor of the same size. Since the motor torque and the motor output have a positive correlation with the electromagnetic gap area, the turbo lag can be shortened, and accordingly, the increase in the TC boost pressure and the reduction in size and weight of the engine can be promoted. More specifically, the motor torque is proportional to the product of the magnetic flux φ and the stator current I. The rotor requires a rotor core having a magnetic path cross-sectional area corresponding to the magnitude of the magnetic flux φ regardless of the type of the motor. The magnetic path length of an AXM rotor having stators on both sides in the axial direction can be significantly reduced because it is formed in the axial direction, and the magnetic path cross-sectional area of the rotor is proportional to the end face area of the rotor, and can be greatly increased. it can. In the end, the amount of magnetic flux is proportional to the end face area of the rotor, and the rotor mass is proportional to the product of the end face area of the rotor and the axial thickness of the rotor. The rotor mass per motor torque can be greatly reduced.

  Furthermore, in an assist motor disposed between the MATC compressor and the turbine, a large amount of heat is transmitted from the high-temperature turbine to the rotor and the bearing through the rotating shaft. In the AXM used in the present invention, since the electromagnetic gap between the rotor and the stator extends in the radial direction along both end faces of the rotor, the air in the electromagnetic gap is urged radially outward by the rotation of the rotor. Resulting in a strong cooling air flow. Since this cooling air flow cools both end faces of the rotor satisfactorily, the temperature rise of the rotor, the rotating shaft and the bearing can be satisfactorily suppressed. The magnetic attractive force of AXM acts in the axial direction on the gap between the stator and the rotor, but TC originally has a thrust bearing function, so there is no need to add a new thrust bearing and the bearing structure is complicated. Can be prevented.

In a preferred aspect, the apparatus includes an assist motor that has a rotor coupled to the rotating shaft and transfers torque to and from the intake-side impeller and the exhaust-side impeller, and a controller that controls the assist motor. When the acceleration is accelerated, the assist motor is electrically operated to reduce the turbo lag. After that, when it is detected that the rotation speed of the motor assist turbocharger or the engine exceeds a predetermined threshold value, the assist motor is operated to generate power and the rotation speed is increased. Suppresses positive overshoot.
That is, the controller electrically operates the assist motor during vehicle acceleration to shorten the turbo lag, and thereafter, when detecting that the MATC or the engine speed exceeds a predetermined threshold value, causes the assist motor to perform a power generation operation to rotate the speed. Suppresses positive overshoot. As a result, the engine speed can be increased to a required value while shortening the turbo lag in accordance with an increase in the accelerator pedal depression amount, and subsequent overshoot can be satisfactorily suppressed.

It is a block diagram which shows Embodiment 1 of the turbocharger (TC) of this invention. FIG. 2 is a schematic axial half-sectional view showing a specific structure example of the TC of FIG. 1. FIG. 3 is a partial circumferential development view of the assist motor of FIG. 2. It is a model axial direction half sectional view of Embodiment 2 of TC of the present invention. It is a block diagram which shows Embodiment 3 of TC of this invention. FIG. 6 is a schematic cross-sectional view showing an example of the exhaust gas flow path structure of FIG. 5. It is a schematic cross section which shows the deformation | transformation aspect 1 of FIG. It is a schematic cross section which shows the deformation | transformation aspect 2 of FIG. It is a block diagram which shows Embodiment 4 of TC of this invention. FIG. 10 is a schematic radial cross-sectional view showing the structure of the intake turbine (intake side impeller) of FIG. 9.

  Embodiments of the present invention will be described below with reference to the drawings. However, the following embodiments do not explain all aspects of the present invention, but only representative aspects.

(Embodiment 1)
A turbocharger (TC) of Embodiment 1 will be described with reference to FIG. FIG. 1 is a block diagram of an engine (internal combustion engine) having a TC of this embodiment. Reference numeral 1 denotes a motor assist turbocharger 1 (MATC), which includes a compressor (intake side impeller) 2, an assist motor 3, and a turbine (exhaust side impeller) 4 connected by a rotating shaft. Reference numeral 5 denotes a DC power source made of, for example, a battery, 6 an inverter, and 7 a controller. The inverter 6 exchanges DC power with the DC power source 5 bidirectionally, and exchanges AC power with the assist motor 3 bidirectionally. The assist motor 3 is composed of a switched reluctance motor (SRM). The controller 7 includes a microcomputer device that controls the operation of the assist motor 3 through the inverter 6 based on detection signals from various sensors (not shown) and commands from the outside.

  Reference numeral 8 is an internal combustion engine (engine), 9 is an intake pipe of the engine 8, 10 is an exhaust pipe of the engine 8, and 11 is a bypass pipe connecting the intake pipe 9 and the exhaust pipe 10. 12 is an intercooler, 13 is an exhaust gas recirculation cooler (EGR cooler), 14 is an exhaust gas recirculation valve (EGR valve), and 15 is a throttle valve. The intercooler 12 cools the pressurized intake air discharged from the compressor 2 and then supplies it to the intake valve of the engine 8 through the throttle valve 15. The EGR cooler 13 cools the exhaust gas flowing from the exhaust pipe 10 and then supplies the exhaust pipe 9 to the intake pipe 9 through the EGR valve 14. The throttle valve 15 adjusts the flow rate of the pressurized intake air that has exited from the intercooler 12. Installation of the throttle valve 15 is not essential. Reference numeral 17 denotes an engine drive motor having a rotor connected to a crankshaft. The engine drive motor 17 can also be constituted by a vehicle AC generator driven by a crankshaft through a timing belt. The engine drive motor 17 is driven by an inverter 18 that exchanges power with the DC power source 5 through a power line 16. The torque assist control of MATC1 will be described below.

  When detecting an increase in the amount of depression of the accelerator pedal, the controller 7 opens the throttle valve 15 according to the amount of depression, and increases the fuel injection amount in the direct injection engine. As a result, the engine speed increases and the vehicle is accelerated. In addition, the controller 7 switches the engine drive motor 17 from the power generation operation to the electric operation at the beginning of the acceleration period (period in which the engine output increases), and electrically operates the assist motor 3. When the engine drive motor 17 is a vehicle AC generator, the power generation is reduced. As a result, the engine 8 is accelerated by the torque difference between the engine drive motor 17 before and after the switching. Moreover, MATC1 is accelerated by the electric torque of MATC1, and a turbo lag is shortened. Thereafter, when it is determined that the increased engine speed has exceeded the threshold speed determined from a predetermined map corresponding to the amount of depression of the accelerator pedal, the assist motor 3 is caused to generate power. Thereby, the overshoot in the positive direction of the rotational speed of the MATC 1 is suppressed, and the engine rotational speed is adjusted to a value corresponding to the amount of depression of the accelerator pedal with good response.

  When the brake pedal is depressed, the controller 7 closes the throttle valve 15 according to the depression amount, and decreases the fuel injection amount in the direct injection engine. As a result, the engine speed is reduced and the vehicle is decelerated. Further, the controller 7 controls the inverter 6 at the initial stage of the deceleration period (period in which the engine output decreases) to cause the assist motor 3 and the engine drive motor 17 to perform a power generation operation. As a result, the MATC 1 becomes low speed after a known turbo lag, and the flow rate and pressure of the pressurized intake air flowing into the engine 8 decrease. Thereafter, when it is determined that the reduced engine speed is lower than the threshold speed determined from a predetermined map corresponding to the amount of depression of the accelerator pedal, the assist motor 3 is operated electrically. Thereby, the overshoot to the negative direction of the rotation speed of MATC1 is suppressed.

A specific structural example of the MATC 1 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a schematic partial axial sectional view of the MATC 1. However, illustration of a casing (housing) surrounding the compressor 2, the assist motor 3, and the turbine 4 is omitted.
Reference numeral 20 denotes a rotating shaft. The impeller 21 of the compressor 2 composed of a radial compressor is fixed to the left end portion of the rotating shaft 20, and the impeller 41 of the turbine 4 composed of a radial turbine is fixed to the right end portion of the rotating shaft 20. The assist motor 3 includes a disk-shaped rotor 30, a front side stator 3F, a back side stator 3B, and a motor housing 31. The motor housing 31 is made of a nonmagnetic metal and is fixed to the inner peripheral surface of a cylindrical casing (not shown). The motor housing 31 includes a disc-shaped front casing 31F and a back casing 31B with ribs. The rib 32F protrudes rearward in the axial direction from the outer peripheral edge of the front casing 31F. The rib 32B protrudes forward in the axial direction from the outer peripheral edge of the back side casing 31B. The front end of the rib 32F and the front end of the rib 32B are abutted, and a motor space S that accommodates the rotor and the stator is defined in the front casing 31F and the back casing 31B. The leading end of the rib 32F and the leading end of the rib 32B that are abutted against each other have a concave portion and a convex portion formed at a constant circumferential pitch. The convex portions of the rib 32F and the rib 32B are abutted in the axial direction. The recesses of the rib 32F and the rib 32B constitute a suction hole 32C for introducing cooling air from the outside into the motor space S. Angular bearings 33F and 33B are provided between the inner peripheral surfaces of the front casing 31F and the back casing 31B and the rotary shaft 20. A sliding bearing and a sliding thrust bearing may be employed instead of the rolling bearing. Reference numeral 34F denotes an air circulation hole provided in the front side casing 31F in the axial direction, and reference numeral 34B denotes an air circulation hole provided in the back side casing 31B in the axial direction.

The rotor 30 includes a support cylinder 30A made of non-magnetic metal and a rotor core 30B fixed to the outer peripheral surface of the support cylinder 30A. The support cylinder 30 </ b> A is fitted and fixed to the rotary shaft 20. Reference numerals 35F and 35B denote support rings that are fitted and fixed to the rotary shaft 20 while sandwiching the support cylinder 30A. The support rings 35F and 35B and the support cylinder 30A may be integrally formed. The rotor core 30B will be described with reference to FIG. The rotor core 30B is formed in a disk shape from a spirally wound electromagnetic steel sheet. The rotor core 30B has holes 30C extending in the radial direction at a predetermined pitch in the circumferential direction by press punching of an electromagnetic steel sheet. Since the hole 30C increases the axial magnetic resistance of the rotor core 30B,
. The region of the hole 30C forms a high magnetoresistive portion of the SRM rotor. Further, the rotor core 30B between the adjacent holes 30C and 30C constitutes a low magnetic resistance part 30D having a small axial magnetic resistance. In this embodiment, the holes 30 </ b> C are configured with a 180-degree pitch (electrical angle π pitch) to form a two-pole SRM rotor. Thereby, this rotor core 30B can comprise the rotor of SRM. An electrically insulating and lightweight centrifugal force reinforcing member such as a fiber reinforced resin member may be provided in the hole 30C.

  FIG. 3 shows a partial circumferential development of the front side stator coil 40F, the back side stator coil 40B, and the rotor core 30B. PH means circumferential direction and AX means axial direction. The front-side stator coil 40F and the back-side stator coil 40B shown in FIG. 3 are arranged apart from each other by an electrical angle π / 2, and are constituted by two-phase coils through which phase currents Ix and Iy flow individually. The front side stator 3F and the back side stator 3B are formed in a disk shape by a spirally wound electromagnetic steel sheet with a slot punched out. The front side stator 3F extends in the radial direction and has a front side stator coil 40F, and the back side stator 3B extends in the radial direction and has a plurality of slots for receiving the back side stator coil 40B. The front-side stator coil 40F and the back-side stator coil 40B can be configured by well-known distributed winding or concentrated winding, like a normal motor stator coil, and a plurality of phase coils are wound with their phases shifted in the circumferential direction. It is constituted by. The phase coils of the same phase of the front side stator coil 40F and the back side stator coil 40B are wound at the same position in the circumferential direction. Thereby, the stator magnetic pole of the back side stator 3B having the same phase as the stator magnetic pole of the front side stator 3F is formed at the same position in the circumferential direction.

  In this way, most of the magnetic flux formed in the rotor core 30B by the front side stator coil 40F and the back side stator coil 40B flows in the rotor core 30B in the axial direction (AX direction). This means that the rotor core 30B does not require a magnetic member for flowing magnetic flux in the circumferential direction. That is, the front / rear stator arrangement axial gap type reluctance motor of this embodiment is a motor that is very lightweight and has a large amount of magnetic flux effective for generating torque that penetrates the rotor. For this reason, the turbo lag of the MATC 1 of this embodiment with this motor is greatly reduced. Further, in order to support the thrust of the compressor 2 and the turbine 4, the MATC 1 originally has a thrust bearing (in this embodiment, constituted by an angular bearing). Therefore, it is not necessary to add a new thrust bearing structure for supporting the axial electromagnetic force of the axial gap motor. The reason why the magnetic flux flowing in the circumferential direction of the rotor core 30B is small is that in this embodiment, the current distribution of the front stator coil 40F and the current distribution of the back stator coil 40B coincide in the circumferential direction. In other words, the circumferential magnetic path cross-sectional area of the rotor core 30B can be greatly reduced by flowing the same spatial phase current through the pair of front and rear stator coils.

  Next, the cooling mechanism of the assist motor 3 will be described with reference to FIG. Reference numeral 4A denotes a ceramic heat insulating disk attached to the rear end face of the back side stator 3B. A groove 42 is formed in the radial direction on the rear end face of the back side stator 3B. Reference numeral 43 denotes a gap between the rear end surface of the heat insulating disk 41 and the rear surface of the impeller 41 of the turbine 4. Similarly, 44 is a gap between the back surface of the impeller 21 of the compressor 2 and the front end surface of the front side stator 3F. Cooling air is introduced into the motor chamber S from the suction hole 32C. The cooling air flows radially inward through the radial gaps between the front side stator 3F and the back side stator 3B and the rotor core 30B, and is discharged through the air circulation holes 34F and the gaps 44. Similarly, the air circulation holes 34B, gaps 42 is discharged. Exhaust gas flowing radially inward from the gap 43 is discharged through the gap 42. Thereby, the assist motor 3 is favorably cooled from the heat of the turbine 4.

  Since the assist motor 3 is composed of SRM, the rotor can be composed of only the rotor core 30B, and the inertial rotating mass can be reduced. In addition, the SRM does not require a sinusoidal magnetic field that requires high-frequency switching for formation, and the MATC requires almost no inverter PWM control. Therefore, the inverter loss and the iron loss of the assist motor 3 can be reduced.

(Embodiment 2)
A turbocharger (TC) of Embodiment 2 will be described with reference to FIG. FIG. 4 is a schematic partial axial sectional view of TC50. The impeller 21 of the compressor 2 is fixed to the left end portion of the rotating shaft 20, and the impeller 41 of the turbine 4 is fixed to the right end portion of the rotating shaft 20. 51C is a casing for the compressor, and 51T is a casing for the turbine. Reference numeral 33 denotes a bearing that rotatably supports the rotary shaft 20. The bearing 33 is supported by a housing integral with the casings 51C and 51T.
52 is an annular flow path of the casing 51C, which forms a ring-shaped diff user. The pressurized intake air discharged from the blades of the compressor 2 to the radially outer side and the circumferential side is sent out to the external intake pipe through the annular flow path 52 and the discharge hole 53. Actually, the discharge hole 53 is provided at the outlet portion of the annular flow path 52 that makes a spiral. 54 is a bypass valve, and 55 is a bypass pipe. The pressurized intake air discharged from the annular flow path 52 to the outside through the discharge hole 53 is sent to an intake manifold (not shown) of the engine. The pressurized intake air is bypassed to the turbine 4 through the bypass pipe 55. The bypass valve 54 is a valve that adjusts the bypass amount of the pressurized intake air.

  Reference numeral 58 denotes an annular flow path of the casing 51T. Exhaust gas discharged from an unillustrated engine is sent to an annular flow path 58 of the casing 51T through a suction hole 56 provided in the casing 51T. Actually, the suction hole 56 is composed of a nozzle provided at the entrance of an annular flow path 58 that makes one round in a spiral shape (not shown). The annular flow path 58 has guide vanes 59 at positions adjacent to the outer peripheral ends of the blade portions of the turbine 4. The guide vanes 59 deflect or accelerate the exhaust gas flow swirling at high speed in the annular flow path 58 toward the one side in the circumferential direction, and spray it on the blade portions of the turbine 4. Reference numeral 57 denotes a second suction hole of the casing 51T. The second suction hole 57 has a guide vane for guiding the pressurized intake air to one side in the circumferential direction, and is open on the side surface of the annular flow path 58.

  In FIG. 4, the exhaust gas flow which is accelerated by the nozzle schematically shown as the suction hole 56 and swirls at high speed in the annular flow path 58 becomes a low pressure, and sucks pressurized intake air from the second suction hole 57. That is, the exhaust gas emitted from the engine is adiabatically expanded through the suction hole 56 that forms a nozzle and is blown into the annular flow path 58 at a high speed. It is sucked into the path 58. That is, the annular flow path 58 constitutes a ring-shaped ejector. The suction hole 56 may be provided on the side surface of the annular channel 52, the second suction hole 57 may be provided on the side surface of the annular channel 58, and the suction hole 56 is provided on the outer peripheral surface side of the annular channel 58. May be.

  The operation of this TC50 will be described. The bypass valve 54 is opened when the flow rates of the compressor 2 and the turbine 4 are small. As a result, a portion of the pressurized intake air that has flowed out of the compressor 2 flows into the turbine 4 through the annular flow path 58 in which the exhaust gas swirls at a high speed. The flow rate increases. As a result, it is possible to reduce the fluid loss of the TC 50 even during engine low power operation. An increase in the pressurized intake air flow rate of the compressor 2 causes an increase in work consumed by the compressor 2, but the pressurized intake air discharged from the compressor 2 is expanded by the turbine 4 to drive the turbine 4, so that Loss decreases.

  Next, the bypass valve 54 is closed when the amount of depression of the accelerator pedal increases to accelerate the engine. As a result, the flow rate of the pressurized intake air sucked into the engine from the compressor 2 immediately increases, and the engine output increases rapidly. Therefore, according to this embodiment, the turbo lag problem during acceleration can be solved with a simple configuration. If the engine output is estimated to be small over a long period of time, the bypass valve 54 may be partially or wholly closed even when the engine output is small. Preferably, the bypass valve 54 is opened when the amount of depression of the brake pedal increases to decelerate the engine. As a result, the flow rate of the pressurized intake air that the engine inhales decreases, and the engine output decreases rapidly. Therefore, according to this embodiment, the turbo lag problem during deceleration can be solved with a simple configuration.

(Embodiment 3)
A turbocharger (TC) of Embodiment 3 will be described with reference to FIG. FIG. 5 is a block diagram of the engine. FIG. 5 is characterized in that, in FIG. 1, the assist motor 3 is omitted and a vortex tube (VT) 60 is added.
The VT 60 has a nozzle 61 into which exhaust gas from the engine 8 flows. VT60 is a cylindrical member. One end of the VT 60 has a high temperature outlet for sending high temperature exhaust gas to the turbine 4, and the other end of the VT 60 has a low temperature outlet for sending low temperature exhaust gas to the EGR cooler 13. 61 is a nozzle provided on the peripheral surface on the other end side of the VT 60, and the nozzle 61 is disposed in the tangential direction of the VT 60. . As a result, a high-speed swirling flow of exhaust gas is formed inside the VT 60. As is well known, the swirl flow that flows through the radial center of the swirl space in the VT 60 has a low temperature, and the swirl flow that flows through the radially outer portion of the swirl space in the VT 60 has a high temperature. As a result, the high-temperature exhaust gas flow swirling at high speed is sent to the turbine 4, and the low-temperature exhaust gas flow is sent to the EGR cooler 13.

  According to this embodiment, since the low-temperature exhaust gas flows into the EGR cooler 13, the cooling burden on the EGR cooler 13 is reduced. Further, since the fine particles contained in the exhaust gas are sent to the turbine 4 by centrifugal force, carbon deposition on the EGR valve 14 and the intake valve of the engine 8 and wear on the cylinder inner surface can be reduced. Also, the hot exhaust gas flow increases the work of the turbine 4. The problem of reducing the work of adiabatic expansion in the turbine 4 due to adiabatic expansion in the vortex tube 60 is improved because the turbine 4 can recover the velocity energy of the high-speed swirling flow exiting the VT 60. That is, the VT 60 also serves as part or all of the adiabatic expansion function of the inlet nozzle (vane) of the turbine 4.

  An example of the flow path structure of the exhaust gas will be described with reference to FIG. An exhaust gas communication pipe 62 communicates the high temperature outlet of the vortex tube 60 and the inlet of the turbine 4. The exhaust gas communication pipe 62 extends in the tangential direction of the VT 60, and blows hot exhaust gas flowing in from the high temperature outlet of the VT 60 into the annular flow path existing on the outer periphery of the turbine 4 in the tangential direction of the turbine 4. The annular flow path of the turbine 4 is disposed so as to surround the turbine 4. The high-temperature outlet of the VT 60 is also composed of an annular flow channel disposed so as to surround one end of the VT 60. The exhaust gas exiting from the annular channel flows into the exhaust gas communication pipe 62 extending in the tangential direction of the VT 60. Reference numeral 63 denotes a low-temperature outlet of the VT 60 that blows out low-temperature exhaust gas to the EGR cooler 13. In this embodiment, the low temperature outlet 63 is arranged on the nozzle 61 side.

(Modification)
A modification is shown in FIG. In this variation, the low temperature outlet 63 is disposed near the exhaust gas communication pipe 62. The exhaust gas communication pipe 62 is disposed in a substantially tangential direction of the VT 60 and the turbine 4.
(Modification)
A modification is shown in FIG. Reference numeral 64 denotes an annular high temperature outlet of the VT 60. In this modification, the exhaust gas communication pipe 62 spirals around and reaches the annular flow path 58 of the turbine 4. VT60 and TC1 are coaxially arranged, and the low-pressure exhaust gas discharge cylinder 44 of TC1 is bent at a right angle.

(Embodiment 4)
A turbocharger (TC) of Embodiment 4 will be described with reference to FIG. FIG. 9 is a block diagram of the engine.
A turbocharger 1 has an intake turbine (intake side impeller) 200 and an exhaust compressor (exhaust side impeller) 400 connected by a rotating shaft. Reference numeral 300 denotes a bearing. 7 is a controller, 8 is an internal combustion engine (engine), and 100 is an electric bypass valve. The bypass valve 100 is configured by an electric butterfly valve controlled by the controller 7. In other words, the bypass valve 100 is a normal throttle valve. The bypass valve 100 is provided in a bypass pipe 10 </ b> D that communicates the outside air intake pipe 101 and the intake pipe 9.

The intake turbine 200 is disposed between the outside air intake pipe 101 and the intake pipe 9. The air flow that flows into the intake turbine 200 from the outside air intake pipe 101 is driven into the intake pipe 9 by driving the intake turbine 200 and is taken into the intake hole of the engine 8. Exhaust gas emitted from the engine 8 flows into the exhaust compressor 400 through the exhaust pipe 10. The exhaust compressor 400 driven by the intake turbine 200 compresses the exhaust gas that has flowed in and discharges it to the downstream exhaust path.
A structural example of the intake turbine 200 will be described with reference to FIG. A disc-shaped impeller 204 is fixed to the left end of the rotating shaft 20. The intake-side impeller 204 is provided with blade portions 205 forming a mixed flow turbine in a radial manner. A casing 201 of the intake turbine 200 encloses an impeller 204 having a blade portion 205. The left end opening of the casing 201 communicates with the intake hole of the engine 8 through the intake pipe 9. The impeller 204 has a large number of wing portions 205 provided radially.

The casing 201 has an annular duct 202 located on the radially outer side of the wing portion 205 and the impeller 204. A nozzle 203 is provided between the annular duct 202 and the radially outer end of the wing portion 205. The external air flow that has flowed into the annular duct 202 flows into the radially outer end of the wing portion 205 through the nozzle 203 while turning in the annular duct 202. The nozzle 203 surrounds the impeller 204 and has a large number of guide plates, and each guide plate extends obliquely with respect to the tangential direction and the radial direction. The radially inner end of each guide plate is displaced in the rotational direction of the impeller 204 as compared to the radially outer end thereof. As a result, the swirling air flow in the annular duct 202 is made high-speed by the nozzle 203 and blown to the wing portion 205 to drive the wing portion 205.
Control of the bypass valve 100 by the controller 7 will be described below. The controller 7 adjusts the opening degree of the bypass valve 100 according to the depression amount of the accelerator pedal. More specifically, the controller 7 determines an increase amount of the intake air amount target value according to the increase amount of the accelerator pedal depression amount, and adjusts the opening degree of the bypass valve 100 according to the increase amount of the intake air amount target value. To do. When the increase amount of the intake air amount target value is large, the opening degree of the bypass valve 100 is increased, and when the increase amount of the intake air amount target value is negative, the opening degree of the bypass valve 100 is decreased. Further, when the intake flow rate exceeds a predetermined value, the intake flow rate is reduced based on the deviation between the detected value of the intake flow rate detected from a flow rate sensor (not shown) provided in the intake pipe 9 and the target value of the intake flow rate. The opening degree of the bypass valve 100 is adjusted in the direction.

  According to this embodiment, since the exhaust pressure of the engine 8 can be reduced when the engine 8 is at a low output, the engine output can be improved. The apparatus of this embodiment can open the bypass valve 100 during sudden acceleration to increase the output of the engine 8 rapidly, and close the bypass valve 100 during low output of the engine 8 to use the intake negative pressure of the engine 8 to engine. 8 is to accelerate the exhaust, thereby increasing the engine torque. The turbocharger 1 can be made significantly smaller than a conventional turbocharger having an exhaust turbine and an intake compressor.

(Modification)
The turbocharger 1 shown in FIG. 9 may be changed to a turbocharger with a motor (motor-assisted turbocharger). For example, when the bypass valve is opened, the motor can be electrically driven to increase the engine torque, and when the bypass valve is closed, the motor can be driven to generate power to reduce the engine torque.

Claims (11)

An exhaust side impeller for transferring torque and exhaust gas flowing from an exhaust pipe of an internal combustion engine mounted on a vehicle, and an intake side impeller for transferring torque and torque flowing into the internal combustion engine from an intake path for intake of outside air In the turbocharger, the two impellers are connected by a rotating shaft that is rotatably supported by the housing.
A nozzle for restricting the intake air flowing into the intake side impeller,
The turbocharger, wherein the intake side impeller is driven by an intake negative pressure of the internal combustion engine and pressurizes the exhaust gas emitted from the internal combustion engine by driving the exhaust side impeller. A bypass valve that is provided in a bypass pipe that bypasses the intake side impeller and flows the intake air into the internal combustion engine and controls the flow rate of the bypass pipe; and a controller that controls the bypass valve;
The turbocharger according to claim 1, wherein the controller opens the bypass valve when the internal combustion engine is accelerated. The controller is
Calculating an error between an intake air amount target value of the internal combustion engine and the intake air amount passing through the intake side impeller;
The turbocharger according to claim 2, wherein the degree of opening of the bypass valve is adjusted so as to eliminate the error. An exhaust side impeller for transferring torque and exhaust gas flowing from an exhaust pipe of an internal combustion engine mounted on a vehicle, and an intake side impeller for transferring torque and torque flowing into the internal combustion engine from an intake path for intake of outside air In the turbocharger, the two impellers are connected by a rotating shaft that is rotatably supported by the housing.
A vortex tube having an inlet through which the exhaust gas flows from the exhaust pipe of the internal combustion engine, a low temperature exhaust outlet for sending the low temperature exhaust gas to the intake pipe, and a high temperature exhaust outlet for discharging the swirling high temperature gas;
The turbocharger, wherein the high temperature exhaust outlet of the vortex tube communicates with an exhaust path upstream of the exhaust side impeller.   The turbocharger according to claim 4, wherein a rotation direction of the exhaust gas in the vortex tube is the same as a rotation direction of the turbine. An exhaust side impeller for transferring torque and exhaust gas flowing from an exhaust pipe of an internal combustion engine mounted on a vehicle, and an intake side impeller for transferring torque and torque flowing into the internal combustion engine from an intake path for intake of outside air In the turbocharger, the two impellers are connected by a rotating shaft that is rotatably supported by the housing.
The exhaust gas is disposed in the exhaust path on the upstream side of the exhaust side impeller to adiabatically expand the exhaust gas to a level lower than the outlet pressure of the intake side impeller, and sucks the pressurized intake air from the intake side impeller to A turbocharger having an ejector for sending to an exhaust side impeller.   The turbocharger according to claim 6, further comprising a bypass valve that is disposed in a bypass pipe that sends the pressurized intake air from the intake side impeller to the ejector to adjust a flow rate of the pressurized intake air. The ejector has an annular passage that is arranged radially outside the exhaust-side impeller and through which the exhaust gas flows annularly.
One of the exhaust gas and the pressurized intake air flows in one of the axial direction and the radial direction and flows into the annular passage,
The turbocharger according to claim 6, wherein the other of the exhaust gas and the pressurized intake air flows in the other of the axial direction and the radial direction and flows into the annular passage. An assist motor that has a rotor coupled to the rotating shaft and transmits and receives torque to and from the intake-side impeller and the exhaust-side impeller;
The turbocharger according to claim 6, wherein the assist motor is a switched reluctance motor. An assist motor that has a rotor coupled to the rotating shaft and transmits and receives torque to and from the intake-side impeller and the exhaust-side impeller;
The assist motor includes a disk-shaped rotor, a front stator that faces the front end surface of the rotor with a small gap in the axial direction, and a back that faces the rear end surface of the rotor with a small gap in the axial direction. An axial gap structure having a side stator,
Magnetic poles of the same phase of the front side stator and the back side stator are arranged at substantially the same circumferential position to generate substantially the same amount of magnetic flux,
The turbocharger according to claim 6, wherein the rotor has a rotor core having a circumferential magnetic path cross-sectional area equal to or less than half of an axial magnetic path cross-sectional area. An assist motor having a rotor connected to the rotating shaft and transferring torque to and from the intake-side impeller and the exhaust-side impeller, and a controller for controlling the assist motor;
The controller electrically operates the assist motor during vehicle acceleration to shorten the turbo lag, and then generates the assist motor when it detects that the motor assist turbocharger or the engine speed has exceeded a predetermined threshold value. The turbocharger according to claim 6, wherein the turbocharger is operated to suppress a positive overshoot of the rotational speed.

Images