JP2012062777A - Electric supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric supercharger having an intake flow passage with low resistance of the passage and no complicated structure and showing high cooling efficiency with respect to a power converter.SOLUTION: The electric supercharger 1 includes a compressor impeller 21, an electric motor 3 driving the compressor impeller 21, and a power converter 4 converting electric power of a battery 5 and supplying the power to the electric motor 3, wherein a compressor housing 22 housing the compressor impeller 21 and an electric motor housing 33 housing the electric motor 3 are integrally structured and the compressor impeller 21 is rotated by the electric motor 3 so as to compress the intake air and to supercharge in the compressor housing 22. The power converter 4 is joined to the outer face of the compressor housing 22 so as to be cooled by air passing through the inside of the compressor housing 22.

Description

  The present invention relates to an electric supercharger including a power conversion device that converts battery power and supplies it to an electric motor.

A technique for providing a supercharger that is driven by an electric motor in order to increase the output of an internal combustion engine for the purpose of reducing fuel consumption of an automobile is known.
Patent Document 1 shows a configuration in which an outlet of an electric supercharger (electric compressor) is connected to an inlet of a turbocharger driven by exhaust gas of an internal combustion engine on an intake passage. According to this configuration, by providing the electric supercharger that can be supercharged freely with electric power, it is possible to increase the acceleration of the internal combustion engine, reduce the back pressure of the internal combustion engine, and reduce unburned fuel. On the other hand, a power conversion device that converts battery power and supplies it to the motor of the electric supercharger needs to be controlled at an ultra-high speed exceeding 100,000 rpm, and generally the battery voltage of an automobile is as low as 14V. Therefore, a large current is required. During continuous operation in such a high rotation / high current state, the loss of the semiconductor element that switches DC power from the battery and the loss due to the wiring resistance increase, and the temperature of the power conversion device rises. Parts may be damaged or deterioration may be accelerated.

  As a countermeasure against such a temperature rise of the power conversion device, for example, in Patent Document 2, in an electric supercharger that supercharges the supply air of an internal combustion engine, a compressor after passing through the heat supply portion of the motor and the power conversion device in the supply air passage A first bypass passage that bypasses the motor and the power converter to the compressor, and a second bypass passage that bypasses the motor, the power converter and the compressor and reaches the internal combustion engine. It is configured to be switchable so as to pass through any of a series flow path, a first bypass flow path, and a second bypass flow path.

Special Table 2000-500544 JP 2003-215075 A

  However, regarding Patent Document 2, although the power conversion device can be cooled, the problem is that the intake flow path becomes complicated, and the intake air resistance of the internal combustion engine because the power conversion device and the electric motor are disposed in the intake flow path. There is a problem that increases significantly.

  In view of the above-described points, an object of the present invention is to provide an electric supercharger having a complicated intake passage and a small passage resistance and high cooling efficiency for a power converter.

  The present invention includes a compressor impeller, an electric motor that drives the compressor impeller, a power conversion device that converts battery power and supplies the electric power to the electric motor, a compressor housing that houses the compressor impeller, and an electric motor housing that houses the electric motor In the electric supercharger that rotates the compressor impeller by the electric motor and compresses the intake air inside the compressor housing to supercharge, the power converter passes through the compressor housing It is joined to the outer surface of the compressor housing so as to be cooled with air.

  According to the electric supercharger of the present invention, the power conversion device is joined to the outer surface of the compressor housing so as to be cooled by the air passing through the inside of the compressor housing. Therefore, the power converter can be efficiently cooled without complicating the intake path.

It is a schematic sectional drawing which shows the whole structure which concerns on Embodiment 1 of this invention. It is a schematic cross section which shows the electric supercharger which concerns on Embodiment 1 of this invention. It is a schematic cross section which shows the electric supercharger which concerns on Embodiment 2 of this invention. It is a schematic cross section which shows the electric supercharger which concerns on Embodiment 3 of this invention. It is a schematic side view which shows the electric supercharger which concerns on Embodiment 4 of this invention. It is a schematic cross section of the electric supercharger according to Embodiment 5 of the present invention. It is a schematic cross section of the electric supercharger according to Embodiment 6 of the present invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
1 is a schematic cross-sectional view showing an overall configuration according to Embodiment 1 of the present invention.
The engine 1 described in this embodiment is a multi-cylinder engine, but here, only one cylinder is shown in FIG. 1 as a cross-sectional view. Engine 100 is a type of engine in which fuel is injected into cylinder 105 by injector 101. A large amount of intake air can be supercharged by a compressor impeller 21 and a turbocharger compressor impeller 111 by an electric motor 3 to be described later, so that not only high output but also low fuel consumption can be realized.

  The engine to be applied is not limited to a direct engine that injects fuel into the cylinder, but may be a port injection engine that injects fuel into the intake passage 108 after the throttle valve.

  In the engine 100, the intake air is first removed of dust and dirt by the air cleaner 115 and then communicated with the upstream passage 114 of the electric supercharger 1. The air compressed by the compressor impeller 21 of the electric supercharger 1 passes from the downstream passage 116 to the intercooler passage 109 via the turbocharger compressor impeller 111.

  The intercooler 113 reduces the temperature of the intake air whose temperature has increased with the increase in pressure due to supercharging, and improves the charging efficiency. Further, the air supercharged through the throttle valve 117 is sucked into the cylinder 105.

  The intake valve 102 is opened and the supercharged air is filled in the cylinder 105 and is ignited and burned by the spark plug 103 together with the fuel injected by the injector 101. As a result, the piston 106 of the engine 100 reciprocates and the crank 107 rotates. The burned air is discharged from the exhaust valve 104 as exhaust gas. The exhaust turbine 112 is driven by the exhaust gas. An exhaust purification catalyst 110 that purifies the exhaust gas is attached.

  The electric supercharger 1 includes a compressor impeller 21, an electric motor 3 that drives the compressor impeller 21, and a power converter 4 that converts electric power of the battery 5 and supplies the electric power to the electric motor 3. Rotate, compress intake air and supercharge.

The power conversion device 4 drives a motor 3 in response to command values such as engine speed, throttle position, suction pressure, and intake air amount. Here, the throttle position reflects the accelerator operation of the driver. For example, in a vehicle without an electronic stall, the accelerator opening may be substituted. Regarding the suction pressure, for example, a pressure sensor or the like can be provided in the intake passage 108 after the throttle valve to obtain the suction pressure. The amount of intake air can be detected by providing an air flow sensor or the like behind the air cleaner 115, for example.

FIG. 2 is a schematic cross-sectional view showing the electric supercharger 1 according to Embodiment 1 of the present invention.
As the electric motor 3, a DC brushless motor, an induction motor, or a synchronous motor is used according to conditions such as capacity and required torque. The power conversion device 4 converts supply power obtained from the battery 5 through the wiring 54 and supplies the converted power to the electric motor 3 through the wiring 43.

  The shaft 23 of the electric supercharger 1 is held by a bearing 24. The compressor housing 22 is a housing that surrounds the compressor impeller 21 and the bearing 24, the electric motor housing 33 is a housing that surrounds the stator 32 and the rotor 31, and the stator 32 is fixed to the electric motor housing 33. The compressor housing 22 and the motor housing 33 are integrally formed.

The AC power output from the power converter 4 is supplied to the stator 32 of the electric motor 3 through the wiring 43, generates a rotating magnetic field, rotates the rotor 31, and is coupled to the rotor 31 via the shaft 23. 21 is rotated.
In addition, although this structure demonstrates the stator winding type motor, in the case of a rotor winding type motor, the output of a power converter device is supplied to a rotor. At this time, since the electric current required for the electric supercharger 1 is large (for example, 200 A or more in the case of a 14V battery), the electronic components such as the semiconductor elements in the power conversion device 4 generate a considerable amount of heat.

  The semiconductor module 41 mounted on the power conversion device 4 includes one or a plurality of semiconductor elements such as IGBTs and MOSFETs, and uses a module including two corresponding to upper and lower arms in an inverter circuit. The input terminals of the semiconductor module 41 are a P terminal 411 for connecting the positive side of the battery, an N terminal for connecting the ground side (not shown for the back of the P terminal), and an upper arm side gate generated by the control board. A G1 terminal 412 for connecting a signal and a G2 terminal 413 for connecting a gate signal on the lower arm side are provided, and an output terminal has an M terminal 414 for connecting an output to a motor. The connection between the P terminal, which is a power system terminal, the N terminal, and the M terminal may be welding using TIG or laser, or may be screwing or soldering. The connection between the G1 terminal 412 and the G2 terminal 413, which are signal systems, may be a solder joint, or a connector or a press-fit connection.

The semiconductor module 41 is joined to the compressor housing 22 via the inclusions 42. Here, when the joining surface of the semiconductor module 41 is an electrode and the compressor housing 22 is used as a conductive member, the inclusion 42 is preferably a member having thermal conductivity and conductivity, such as solder or silver paste, When it is desired to ensure insulation, the inclusion 42 is preferably a thermally conductive grease or adhesive, or a member having thermal conductivity and insulation such as an insulating substrate.
When joining the joining surface of the semiconductor module 41 on a circuit pattern, it joins to the compressor housing 22 via an inclusion in the circuit pattern. When the semiconductor element is used without being modularized, the semiconductor element is joined to the compressor housing 22 via inclusions or circuit patterns and inclusions. Similarly, electronic components that generate heat, such as capacitors, other than the semiconductor module 41 may be joined to the compressor housing 22 via inclusions or circuit patterns and inclusions.

The power conversion device 4 includes a semiconductor module 41 on which a semiconductor element is mounted, an electronic component such as a capacitor, and a control board 44 including a control signal generation circuit and a protection circuit for driving the semiconductor element in a case 45, and the direct current of the battery Electric power is converted into AC power required by the motor 3. The material of the case 45 may be a resin, but a material with high thermal conductivity such as aluminum is preferable in order to improve heat dissipation.
Here, since electronic components that generate heat such as the semiconductor module 41 and the capacitor are mounted at the bottom of the power conversion device 4 with priority on heat dissipation, the electronic components such as the semiconductor module 41 and the capacitor are joined to the compressor housing 22. Is equivalent to joining the power converter 4 to the compressor housing 22. By joining the power conversion device 4 to the compressor housing 22 in this manner, the electronic components that generate heat can be cooled using the air passing through the compressor housing 22.
In order to improve the adhesion between the heat-generating electronic component and the compressor housing 22 and reduce the thermal resistance, the power converter 4 is screwed to the compressor housing 22 or power is supplied using a band or a clamp. It is preferable to sandwich the conversion device 4 and the compressor housing 22.

  As described above, according to the first embodiment of the present invention, the compressor impeller 21, the electric motor 3 that drives the compressor impeller 21, and the power converter 4 that converts the electric power of the battery 5 and supplies the electric power to the electric motor 3 are provided. The compressor housing 22 that houses the compressor impeller 21 and the motor housing 33 that houses the electric motor 3 are integrally configured, and the compressor impeller 21 is rotated by the electric motor 3 to compress the intake air inside the compressor housing 22 and supercharge In the electric supercharger 1, the power conversion device 4 is joined to the outer surface of the compressor housing 22 so as to be cooled by the air passing through the compressor housing 22. Since heat can be dissipated in the housing 22, the intake path is complicated. It can be carried out efficiently cool the power converter 4 without.

Embodiment 2. FIG.
FIG. 3 is a schematic sectional view showing an electric supercharger 1 according to Embodiment 2 of the present invention.
In the electric supercharger 1 of the first embodiment, in order to increase the heat capacity and increase the time constant when the temperature rise of the electronic components that generate heat is steep, the heat storage member between the power converter 4 and the compressor housing 22 is used. 60 is provided.
The heat storage member 60 is preferably a high thermal conductivity member such as aluminum or copper. Further, the heat storage member 60 and the compressor housing 22 are joined in the same manner as the method of joining the semiconductor module 41 to the compressor housing 22 as described above.
Note that it is preferable that the heat storage member 60 be provided as an integral part of the compressor housing 22 with a thicker compressor housing 22 because the assembly is simple.

Embodiment 3 FIG.
FIG. 4 is a schematic cross-sectional view showing an electric supercharger 1 according to Embodiment 3 of the present invention.
The electronic components such as the semiconductor module 41 of the power conversion device 4 in the first and second embodiments are only required to be bonded to the compressor housing 22 with low heat, and may be arranged at the positions shown in FIG.
4A, the semiconductor module 41 is joined to the bearing portion of the compressor housing 22, and FIG. 4B, the semiconductor module 41 is joined to the side surface of the air compression portion of the compressor housing 22. In c), the semiconductor module 41 is joined to the surface of the compressor housing 22 opposite to the electric motor 3.
4A to 4C, the heat storage member may be disposed between the inclusion 42 and the compressor housing 22, and the compressor housing as shown in FIG. 4D. The heat storage member 60 is joined to the surface of the electric motor 22 and the semiconductor module 41 is joined in the radial direction of the shaft 23.

Embodiment 4 FIG.
FIG. 5 is a schematic side view showing an electric supercharger 1 according to Embodiment 4 of the present invention.
Fig.5 (a) is the figure seen from the axial direction by the side of an electric motor in FIG.2 and FIG.3. A circle indicated by a dotted line near the center indicates a bearing portion of the compressor housing 22, and the power conversion device 4 is disposed outside the bearing portion between the compressor housing 22 and the electric motor housing 33.
When the electric motor 3 is a three-phase electric motor and the semiconductor module 41 has semiconductor elements for one phase, that is, upper and lower arms, three semiconductor modules 41 are mounted on the power conversion device 4. When the case 45 of the power conversion device 4 is provided so that three semiconductor modules 41 can be mounted side by side, the case 45 has the rectangular shape shown in the figure.
In addition to the rectangle, the case 45 may have a shape corresponding to the arrangement of the control board, electronic components, wiring, and the like. When the case 45 exceeds the center of the compressor housing 22 in the radial direction, a U-shape is formed as shown in FIG. But you can.
Moreover, in order to improve heat dissipation, it is preferable to arrange each semiconductor module at an angle in the radial direction of the compressor housing 22 as shown in FIG. In this case, the wiring of the three-phase each phase of the motor 3 is often shifted by 120 degrees in the radial direction, and the semiconductor module 41 is disposed so as to correspond to these wirings, whereby the motor 3 and the semiconductor module 41 are arranged. There is also an advantage that the wiring is shortened and the loss and inductance are reduced.
4A to 4D, the semiconductor modules 41 may be arranged side by side or arranged at an angle in the radial direction.

  In addition, in order to endure high rotation of the compressor impeller 21 and the rotor 31, the axial length of the bearing 24 becomes long, and a large gap is generated between the compressor impeller 21 and the rotor 31, so that the power conversion device is formed in this gap. By arranging 4, the electric supercharger 1 can be reduced in size.

Embodiment 5 FIG.
6 is a schematic cross-sectional view showing an electric supercharger 1 according to Embodiment 5 of the present invention.
In the first to fourth embodiments, in order to further improve the heat dissipation, there is a means for expanding the heat dissipation area, and it is preferable to provide fins as the method.
In FIG. 6A, straight fins are arranged radially in the compressor housing 22 as the fins 70, and the fins 70 are arranged directly in the portion through which air passes, so that heat dissipation is improved. In this case, since the intake resistance increases, it is arranged in consideration of the balance between heat dissipation and intake capacity.
6B, the fin 70 is provided on the side of the air compression portion of the compressor housing 22 over the outer periphery, and FIG. 6C is the fin 70 provided on the surface of the compressor housing 22 on the electric motor 3 side.
6A to 6C are examples in which the fins 70 are provided radially on the compressor housing 22, and FIGS. 6D to 6G are examples in which the fins 70 are provided on the case 45 of the power converter 4. 6 (d) is FIG. 4 (a), FIG. 6 (e) is FIG. 4 (b), FIG. 6 (f) is FIG. 4 (c), FIG. 6 (g) is FIG. This corresponds to FIG.
The fin 70 may be provided on the heat storage member 60.

  The fin 70 may be provided on the heat storage member 60. Further, the fin 70 may be a fin such as a pin fin or a wavy fin other than the straight fin shown in the drawing. Further, although the fins 70 are described as being arranged radially or over the outer periphery, the heat dissipation can be improved even if the fins 70 are arranged only in the vicinity of a heat-generating electronic component such as a semiconductor element in consideration of the heat dissipation.

Embodiment 6 FIG.
FIG. 7 is a schematic sectional view showing an electric supercharger 1 according to Embodiment 6 of the present invention.
In the first to fifth embodiments, as a method for expanding the heat radiation area, a metal frame 80 of the vehicle body may be used as shown in FIG.
7A, the side of the air compression portion of the compressor housing 22 is joined to the metal frame 80 of the vehicle body, and FIG. 7B is the electric power converter 4 joined to the metal frame 80 of the vehicle body. For these joining, it is preferable to use a silicone grease, an adhesive, a heat conductive sheet, or the like, which is a heat conductive member.

  With the above configuration, by joining electronic components such as semiconductor elements in the power converter 4 of the electric supercharger 1 to the compressor housing 22 and cooling their heat with air passing through the compressor housing 22, Heat can be radiated without increasing the intake resistance.

DESCRIPTION OF SYMBOLS 1 Electric supercharger 21 Compressor impeller 22 Compressor housing 23 Shaft 24 Bearing 3 Electric motor 31 Rotor 32 Stator 33 Electric motor housing 4 Power converter 41 Semiconductor module 42 Inclusion 43 Wiring 44 Control board 45 Case 5 Battery 54 Wiring 60 Thermal storage member 70 Fin 80 Metal frame of car body

Claims (6)

A compressor impeller, an electric motor that drives the compressor impeller, a power conversion device that converts battery power and supplies the electric motor to the electric motor, and a compressor housing that houses the compressor impeller and an electric motor housing that houses the electric motor are integrated. In the electric supercharger configured to rotate the compressor impeller by the electric motor and compress the intake air inside the compressor housing to supercharge
The electric supercharger is joined to an outer surface of the compressor housing so as to be cooled by air passing through the compressor housing.   The electric supercharger according to claim 1, wherein the power converter is joined to an outer surface of the compressor housing via a heat storage member.   The said power converter device contains a semiconductor module, and this semiconductor module is joined to the surface on the opposite side to the bearing part of the said compressor housing, an air compression part, or the said electric motor. Electric supercharger.   4. The electric supercharger according to claim 1, wherein the power converter is disposed between the electric motor housing and the compressor housing. 5.   The electric supercharger according to any one of claims 1 to 4, wherein a heat radiating fin is provided in the compressor housing or the power converter.   The electric supercharger according to any one of claims 1 to 5, wherein the compressor housing or the power converter is joined to a metal frame of a vehicle body.

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