JP5707852B2 - Electric assist turbocharger - Google Patents

Description

  The present invention relates to an electrically assisted turbocharger in which an electric motor (motor) is combined with a turbocharger.

  In a system in which a turbocharger is added to the engine, when the engine speed is low and the torque is low, the exhaust gas energy is small, so that the exhaust turbine has a low speed and the amount of intake air supercharged by the intake compressor is small. For this reason, if a high torque is required at the time of low engine rotation, the intake amount is insufficient with respect to the request coming from the fuel injection amount. In addition, during transient operation where the engine condition fluctuates, the rotation of the turbocharger is delayed in response to fluctuations in the engine condition due to the rotational inertia of the turboshaft. For example, the vehicle rapidly increases the fuel injection amount for acceleration When you want to make it happen, the turbocharger rotates slowly and the intake volume does not increase rapidly.

  On the other hand, an electric assist turbocharger in which an electric motor is combined with a turbocharger is known. The electric assist turbocharger can freely control the supercharging pressure even when the driving force of the exhaust turbine is small by assisting the driving of the turboshaft with the power of the electric motor at the time of low engine speed or transient operation.

  A conventional electrically-assisted turbocharger is a turbocharger having an exhaust turbine rotated by exhaust gas and an intake compressor connected to the exhaust turbine via a turboshaft. And an electric motor having a stator positioned at the center.

  In this electrically assisted turbocharger, since the rotor of the electric motor is provided integrally with the turbo shaft, the rotor rotates at the same rotational speed as the turbo shaft.

JP 2004-169629 A JP 2006-320143 A

  However, in a general electric motor, there is a region where the copper loss is large in a region where the rotational speed is low, and there is a region where the iron loss is large in a region where the rotational speed is high. Copper loss is due to the current flowing in the winding. Iron loss occurs because electrical energy is consumed by eddy currents flowing through the iron core. More specifically, the iron loss includes eddy current loss and hysteresis loss, both of which increase according to the rotational speed.

  Since a general electric motor has a large iron loss when the rotation speed is high, an appropriate use rotation speed is set in a range of several thousand rpm to 20,000 rpm.

  On the other hand, the turbocharger rotates at a higher speed as the exhaust gas increases. For example, a turbocharger mounted on a small engine may have a rotation speed of 100,000 to 200,000 rpm. This rotational speed corresponds to a region where eddy current loss is large in a general electric motor.

  As described above, in the conventional electric assist turbocharger, the rotor of the electric motor has the same rotational speed as that of the turbo shaft, so the electric motor is used in a rotational speed region that is not recommended, and wasteful power consumption due to iron loss. Is inevitable.

  Although there is an ultra-high-speed motor that can suppress an increase in iron loss even at ultra-high speed rotation exceeding 100,000 rpm, it is expensive because it uses a special material and structure, and is not suitable for mounting on a popular vehicle.

  In addition, when the electric motor is not used, the rotor does not need to be operated. However, since the rotor is provided integrally with the turbo shaft, even when the electric motor is not used, the rotor rotates when the turbo shaft rotates, which is useless. There is also the problem that work is occurring.

  Furthermore, it is desired to improve the fuel consumption by regenerating energy using surplus exhaust gas energy as electric power in the engine high speed range.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electric assist turbocharger that can reduce iron loss of an electric motor, eliminate wasteful work when the electric motor is stopped, and enable energy regeneration.

The present invention devised to achieve this object is an electrically assisted turbocharger configured by connecting a turbocharger and an electric motor by a reduction gear mechanism, and the reduction gear mechanism is attached to a turbo shaft of the turbocharger. a turbo-side gear mounted, said being connected to the turbo-side gear with attached to the motor rotor, and has an electric motor-side gear is larger number of teeth than the turbo-side gear, the turbo-side gear The rotation of the electric motor is accelerated through the two-way clutch, the motor-side gear, and the turbo-side gear and transmitted to the turbo shaft, and the two-way clutch Is arranged with a polygonal inner ring fixed to the turboshaft, a predetermined gap from the inner ring, and the tag. An outer ring fixed to Bo gear, an electric assisted turbocharger comprising a.

  The two-way clutch transmits a driving force from the electric motor to the turbo shaft during assist, transmits a driving force from the turbo shaft to the electric motor during energy regeneration, and between the electric motor and the turbo shaft at other times. It may be configured not to transmit the driving force.

The two-way clutch, prior Symbol further comprising a locking mechanism disposed in a gap between the inner ring and the outer ring, the locking mechanism includes a plurality of rollers provided between the outer ring and the sides of the inner ring, a retainer for changing the position of the roller relative to the inner ring holds the arrangement interval thereof roller, may consist.

  According to the present invention, it is possible to provide an electric assist turbocharger that can reduce the iron loss of the electric motor, eliminate unnecessary work when the electric motor is stopped, and enable energy regeneration.

1 is a side view showing an electrically assisted turbocharger according to an embodiment of the present invention. (A) is a front view which shows the reduction gear mechanism of the electrically assisted turbocharger of FIG. 1, (b) is sectional drawing which shows an example of a two-way clutch. It is a figure explaining the principle of a two-way clutch.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a side view showing an electrically assisted turbocharger according to a preferred embodiment of the present invention.

  As shown in FIG. 1, the electrically assisted turbocharger 10 according to the present embodiment is configured by connecting a turbocharger 11 and an electric motor 12 by a reduction gear mechanism 13.

  The turbocharger 11 coaxially connects the exhaust turbine 14 rotated by exhaust gas, the intake compressor 15 that compresses air by rotation, the exhaust turbine 14 and the intake compressor 15, and the intake compressor 15 from the exhaust turbine 14 side. And a turbo shaft 16 for transmitting rotation to the side. The turbo shaft 16 is supported at two locations by a bearing 17 on the exhaust turbine 14 side and a bearing 18 on the intake compressor 15 side.

  As shown in FIG. 2A, the reduction gear mechanism 13 is connected to the turbo side gear 19 attached to the turbo shaft 16 of the turbocharger 11, the rotor 20 of the electric motor 12, and to the turbo side gear 19. The motor-side gear 21 has more teeth than the turbo-side gear 19.

  The turbo gear 19 is attached to the turbo shaft 16 via a two-way clutch 22 as shown in FIG. The two-way clutch 22 is arranged with a polygon (an octagonal shape in the figure) -like inner ring (cam) 23 fixed to the turbo shaft 16 and a predetermined gap from the inner ring 23 and is fixed to the turbo-side gear 19. And an outer ring 24 and a lock mechanism 25 disposed in a gap between the inner ring 23 and the outer ring 24.

  The lock mechanism 25 is provided with a plurality (eight in the figure) of rollers 26 provided between each side of the inner ring 23 and the outer ring 24, and the arrangement interval of the rollers 26 is maintained, and the position of the roller 26 with respect to the inner ring 23 is changed. And a cage 27 to be made.

  In the two-way clutch 22, the position of the roller 26 with respect to the inner ring 23 is changed by rotating the cage 27, and the inner ring 23 and the outer ring 24 can be locked and unlocked.

  Specifically, as shown in FIG. 3 (a), the retainer 27 is rotated so that the roller 26 moves forward in the rotational direction of the inner ring 23 so as to assist the motor 12 at low engine speed when exhaust gas energy is insufficient. Positioned on the apex side, the inner ring 23 is locked to rotate following the rotation of the outer ring 24 by the wedge effect, and the driving force is transmitted from the electric motor 12 to the turbo shaft 16.

  On the other hand, in order to regenerate the surplus exhaust gas energy as electric power in the engine high speed range, as shown in FIG. The outer ring 24 is locked to rotate following the rotation of the inner ring 23 by the wedge effect, and the driving force is transmitted from the turbo shaft 16 to the electric motor 12.

  Further, when not assisting or regenerating energy, as shown in FIG. 3C, the cage 27 is rotated so that the roller 26 is positioned at the center of each side of the inner ring 23, and the inner ring 23 and the outer ring 24 are moved. The lock is released so that the driving force is not transmitted between the electric motor 12 and the turbo shaft 16.

  Next, the operation of the electric assist turbocharger 10 will be described.

  In the electrically assisted turbocharger 10, when the rotational speed of the turbo shaft 16 is low and the intake air amount supercharged from the intake compressor 15 is small, it is necessary to increase the intake air amount in order to increase the fuel injection amount.

  In such a case, the lock mechanism 25 of the two-way clutch 22 is controlled so that the inner ring 23 follows and rotates with respect to the rotation of the outer ring 24, and then the motor 12 is rotated to rotate the motor side gear. The rotation of the turbo shaft 16 is assisted from 21 through the turbo gear 19 and the two-way clutch 22. At this time, since the rotation of the electric motor 12 is accelerated and transmitted to the turbo shaft 16, the electric motor 12 may be rotated at a lower rotational speed than the desired rotational speed of the turbo shaft 16.

  During a transient operation (for example, during overtaking operation) in which the engine state is changed to a higher-load engine state with the rotational speed of the turbo shaft 16 being high, the rotation of the turbo shaft 16 is performed by rotating the motor 12. Assist. At this time, the rotational speed of the turbo shaft 16 is high, but the rotational speed of the electric motor 12 is lower than the desired rotational speed of the turbo shaft 16, so the electric motor 12 is used in a rotational speed region where the iron loss is small. The

  On the other hand, when the rotational speed of the turbo shaft 16 is higher than the rotational speed of the turbo gear 19 during high-load operation, the lock mechanism 25 of the two-way clutch 22 is controlled to prevent the inner ring 23 from rotating. By locking the outer ring 24 so as to follow and rotate, the motor 12 is rotated using the driving force of the turbo shaft 16 to generate electric power.

  In other cases, the two-way clutch 22 is idled by controlling the lock mechanism 25 of the two-way clutch 22 to release the lock between the inner ring 23 and the outer ring 24, and the driving force is generated between the rotor 20 and the turbo shaft 16. Do not communicate. As a result, when the electric motor 12 is not operating, the driving force of the turbo shaft 16 is not transmitted to the rotor 20, and no unnecessary work is performed. This can be transmitted to the compressor 15.

  As described above, the electrically-assisted turbocharger 10 according to the present embodiment only needs to rotate the electric motor 12 at a lower rotational speed than the desired rotational speed of the turbo shaft 16 and reduce the iron loss of the electric motor 12. be able to. That is, according to the electrically assisted turbocharger 10, wasteful consumption of electric power due to iron loss is reduced, and as a result, fuel consumption is suppressed, so that fuel efficiency can be improved.

  Further, in the electrically assisted turbocharger 10 according to the present embodiment, since the electric motor 12 is operated at a low rotational speed, it is not necessary to employ an ultra-high speed motor, and an electric motor having a general material and structure can be employed. Can be suppressed.

  Further, since the turbo gear 19 is attached to the turbo shaft 16 via the two-way clutch 22, useless work when the motor 12 is stopped can be eliminated, and the driving force of the exhaust turbine 14 can be sucked more efficiently. It becomes possible to transmit to the compressor 15 and to regenerate energy when there is surplus exhaust gas energy.

  Therefore, when the electrically assisted turbocharger 10 having such a configuration is mounted on an engine, fuel consumption can be improved by reducing friction and regenerating energy.

  The gear ratio between the motor-side gear 21 and the turbo-side gear 19 is preferably 5: 1 to 20: 1. For example, if the gear ratio is 10: 1, the motor 12 is rotated when the rotational speed of the turbo shaft 16 is 200,000 rpm. The rotational speed of 20,000 rpm is sufficient.

  Further, the two-way clutch 22 is not limited to the configuration shown in FIG. 2B and FIGS. 3A to 3C, and may have any configuration as long as it functions as a two-way clutch. May be.

DESCRIPTION OF SYMBOLS 10 Electric assist turbocharger 11 Turbocharger 12 Electric motor 13 Reduction gear mechanism 14 Exhaust turbine 15 Intake compressor 16 Turbo shaft 17 Bearing (exhaust turbine side)
18 Bearing (intake compressor side)
19 Turbo side gear 20 Rotor 21 Motor side gear 22 Two-way clutch 23 Inner ring 24 Outer ring 25 Lock mechanism 26 Roller 27 Cage

Claims (3)

An electrically assisted turbocharger configured by connecting a turbocharger and an electric motor with a reduction gear mechanism,
The reduction gear mechanism is
A turbo-side gear attached to a turbo shaft of the turbocharger;
An electric motor-side gear attached to the rotor of the electric motor and connected to the turbo-side gear, and having more teeth than the turbo-side gear ;
Have
The turbo side gear is attached to the turbo shaft via a two-way clutch, and the rotation of the electric motor is accelerated through the two-way clutch, the electric motor side gear, and the turbo side gear and transmitted to the turbo shaft. And
The two-way clutch includes a polygonal inner ring fixed to the turbo shaft, and an outer ring disposed with a predetermined gap from the inner ring and fixed to the turbo side gear. Assist turbocharger.   The two-way clutch transmits a driving force from the electric motor to the turbo shaft during assist, transmits a driving force from the turbo shaft to the electric motor during energy regeneration, and between the electric motor and the turbo shaft at other times. The electrically assisted turbocharger according to claim 1, wherein the electrically assisted turbocharger is configured not to transmit a driving force. The two-way clutch is
Further comprising a locking mechanism disposed in a gap between the front Symbol inner and the outer ring,
The locking mechanism is
A plurality of rollers provided between each side of the inner ring and the outer ring;
A cage that holds the arrangement interval of the rollers and changes the position of the rollers with respect to the inner ring ;
The electrically assisted turbocharger according to claim 1 or 2.

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