JP5707853B2 - Electric assist turbocharger cooling system - Google Patents

Description

  The present invention relates to an electric assist turbocharger in which an electric motor (motor) is combined with a turbocharger, and more particularly to an electric assist turbocharger cooling device for cooling an electric assist turbocharger motor.

  As shown in FIG. 2, the turbocharger 20 is configured by connecting a turbine 21 and a compressor 22 with a turbo shaft 23. The turbine 21 includes a turbine housing 25 that surrounds the turbine wheel 24 and into which exhaust gas is introduced. The compressor 22 includes a compressor housing 27 that surrounds the compressor wheel 26 and into which intake air is introduced. The turbine wheel 24 and the compressor wheel 26 are The turbo shaft 23 to be connected is accommodated in a bearing housing 28 and is supported by a bearing portion 29 provided in the bearing housing 28. A lubricating oil inlet 30 for supplying lubricating oil to the bearing portion 29 is provided in the upper portion of the bearing housing 28, and a lubricating oil discharge port 31 is formed in the lower portion, and the lubricating oil from the engine is supplied to the bearing portion in the bearing housing 28. The cooling chamber 32 is supplied.

  FIG. 3 shows an intake / exhaust system and a cooling system using lubricating oil when the turbocharger 20 is added to the engine 40.

  In the turbocharger 20, the turbine 21 is connected to the exhaust pipe 41 of the engine 40, the compressor 22 is connected to the intake pipe 42, and exhaust gas exhausted from the combustion chamber 43 of the engine 40 is supplied to the turbine 21 through the exhaust pipe 41. The turbine 21 is driven, and the intake air is introduced into the compressor 22 from the air cleaner 44 and compressed, cooled by the intercooler 46 via the intake throttle 45, and introduced into the combustion chamber 43 of the engine 40.

  The turbocharger 20 uses lubricating oil from the engine 40 through the oil supply pipe 47 to lubricate the bearing portion 29 in the bearing housing 28 and cool the bearing portion 29 by receiving heat from exhaust gas. The bearing portion 29 is introduced into the bearing portion cooling chamber 32 to lubricate and cool the bearing portion 29, and the lubricating oil supplied to the bearing portion cooling chamber 32 is supplied from the lubricating oil discharge port 31 to the oil return pipe. The oil pan is returned to 48 and is circulated again to the bearing cooling chamber 32.

  In the system in which the turbocharger 20 is added to the engine 40, there is a problem that the boost pressure rises in a low rotation range of the engine and the output characteristics of the engine are not good even when high torque is required at low rotation.

  Therefore, recently, the motor rotor is directly connected to the turbo shaft of the turbocharger, and when high torque is required, the turbo shaft is rotated by the motor to increase the supercharging pressure, and conversely, the motor is generated by rotating the turbine. An electrically assisted turbocharger used as the above has been developed (Patent Documents 1 and 2).

JP 2004-169629 A JP 2006-320143 A

  In this electrically assisted turbocharger, a motor is installed between the bearing housing and the compressor housing. However, when the motor is driven, the temperature of the motor rises to 200 ° C. or more due to self-heating of the stator and heat received from the turbine. There is a problem that the driving force is reduced.

  FIG. 4 shows motor speed characteristics and motor current characteristics with respect to torque when the motor temperature is −20 ° C., + 20 ° C., and + 70 ° C. When the motor temperature is high, the motor current characteristics and speed characteristics are poor. Become.

  Therefore, when the motor temperature rises to 100 ° C. or more, the boost rise time is delayed, exhaust gas performance and driving response are deteriorated, and the heat resistance of the motor is also problematic.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cooling device for an electric assist turbocharger that can solve the above-described problems and can cool the motor of the electric assist turbocharger.

The present invention was invented in order to achieve this object, in the cooling system of an electric assisted turbocharger that features a motor case in a bearing housing journalled turbo shaft of the turbocharger, cooling motor which is formed in the motor case a chamber, said bearing bearing unit for cooling chamber formed in the housing, a communication oil passage communicating with said bearing portion cooling chamber and the motor cooling chamber is formed in a top of the motor cooling chamber a lower portion formed lubricating oil inlet of the motor casing, and the lower the formed lubricating oil discharge port of the bearing housing consists of, said motor pressurized lubricating oil from the engine through the lubricating oil inlet the bearing portion for the cooling chamber the lubricating oil filled in the cooling chamber for the motor through the communication oil passage while being introduced into use cooling chamber After being introduced, electrically assisted turbo, characterized in that the lubricating oil introduced into the cooling chamber for the bearing portion to form a cooling lubricant circuit, which is circulated is discharged through to fall the lubricant oil discharge port by gravity This is a charger cooling device.

  The motor case may be provided so as to connect the bearing housing and a compressor housing of the turbocharger.

  INDUSTRIAL APPLICABILITY The present invention has an excellent effect that the cooling performance of the stator of the motor is improved, the reduction in motor driving force can be prevented, and the power generation efficiency can be improved when the motor is used as a generator.

It is a cross-sectional schematic diagram which shows the electrically assisted turbocharger which concerns on embodiment of this invention. It is sectional drawing which shows the conventional turbocharger. It is the figure which incorporated the conventional turbocharger in the engine intake-exhaust system. It is a figure which shows the speed characteristic and electric current characteristic with respect to the torque in each temperature of a motor.

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

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

  In FIG. 1, reference numeral 10 denotes an electrically assisted turbocharger. Except for the configuration of the motor 11, the turbine and the compressor are basically the same as the structures of the turbine 21 and the compressor 22 of the turbocharger 20 described in FIG. The same reference numerals are given and the description thereof is omitted.

  The bearing housing 28 and the compressor housing 27 are connected by a motor case 12, and the motor 11 is provided in the motor case 12 to constitute the electrically assisted turbocharger 10. That is, the motor 11 is configured to be disposed on the low-temperature compressor side instead of the high-temperature turbine side. The reason for this configuration is that the motor 11 generally exhibits its performance at a lower temperature.

  The motor 11 includes a rotor 13 coupled to a turbo shaft 23 and a stator 14 disposed on the outer periphery of the rotor 13 via an air gap. The motor case 12 supports and surrounds the stator 14 as appropriate. And a motor cooling chamber 15 is formed in the motor case 12.

  Here, considering that the lubricating oil from the engine is supplied to the motor cooling chamber 15 and the bearing cooling chamber 32 in order to cool and lubricate the motor 11 and the bearing 29, the motor cooling chamber 15 and the bearing It is assumed that the lubricating oil is supplied to each of the part cooling chambers 32 through a separate path.

  However, this method has a problem that the cooling and lubrication circuit for cooling and lubrication becomes a plurality of circuits, and the configuration becomes complicated due to an increase in the number of circuits.

  Therefore, in the present invention, the motor cooling chamber 15 and the bearing cooling chamber 32 communicate with each other, the lubricating oil inlet 33 is formed in the motor case 12, and the lubricating oil discharge port 34 is formed in the bearing housing 28, so that the engine A cooling lubrication circuit 35 for sequentially supplying the lubricating oil from the motor cooling chamber 15 and the bearing cooling chamber 32 to the motor cooling chamber 15 is formed to constitute a cooling device for the electric assist turbocharger.

  For this purpose, a communication oil passage 36 that communicates with the bearing cooling chamber 32 in the bearing housing 28 and supplies lubricating oil to the upper portions of the two bearings 29 is formed in the upper part of the motor cooling chamber 15. As a result, a space in which the motor cooling chamber 15 and the bearing cooling chamber 32 communicate with each other at the upper portion thereof is formed.

  A cooling system using the lubricating oil shown in FIG. 3 is connected between the lubricating oil inlet 33 and the lubricating oil outlet 34. Specifically, an oil supply pipe 47 is connected to the lubricating oil inlet 33, and an oil return pipe 48 is connected to the lubricating oil outlet 34.

  As a result, the lubricating oil from the engine is introduced into the motor cooling chamber 15 in the motor case 12 through the oil supply pipe 47 and the lubricating oil inlet 33 by the pressurizing means (not shown) as described with reference to FIG. 12 is cooled to the bearing chamber cooling chamber 32 in the bearing housing 28 through the communication oil passage 36 to lubricate and cool the bearing portion 29 in the bearing housing 28, and the lubricating oil is fed by gravity. The oil is returned from the discharge port 34 to the oil pan through an oil return pipe 48 and circulated.

  Next, the operation of the present embodiment will be described.

  When a high torque is required at a low load and the boost pressure is increased, the rotor 13 is rotated by energizing the coil of the stator 14 of the motor 11, the compressor 22 is driven via the turbo shaft 23, and the turbine 21 When power is generated from driving, the battery is charged with a regenerative current generated in the coil of the stator 14.

  Since the stator 14 generates heat at 200 ° C. when the motor 11 is driven, the temperature of the motor 11 is cooled to 80 ° C. or less by flowing lubricating oil from the engine into the motor cooling chamber 15 in the motor case 12. Can do.

  Next, the lubricating oil supplied to the motor cooling chamber 15 flows to the bearing cooling chamber 32 in the bearing housing 28 through the communication oil passage 36, cools the bearing 29, and then returns the oil from the lubricating oil discharge port 34. Returned to tube 48.

  In this way, the lubricating oil is sequentially supplied from the motor cooling chamber 15 to the bearing cooling chamber 32, whereby the motor 11 that is most required to have a cooling effect can be preferentially cooled. Since efficiency can be increased, motor efficiency is improved. Moreover, since the cooling lubrication circuit 35 can be comprised by one circuit, a structure can be simplified.

DESCRIPTION OF SYMBOLS 10 Electric assist turbocharger 11 Motor 12 Motor case 13 Rotor 14 Stator 15 Motor cooling chamber 20 Turbocharger 21 Turbine 22 Compressor 23 Turbo shaft 24 Turbine wheel 25 Turbine housing 26 Compressor wheel 27 Compressor housing 28 Bearing housing 29 Bearing part 30 Lubricating oil Inlet 31 Lubricating oil outlet 32 Bearing cooling chamber 33 Lubricating oil inlet 34 Lubricating oil outlet 35 Cooling lubrication circuit 36 Connection oil passage 40 Engine 41 Exhaust pipe 42 Intake pipe 43 Combustion chamber 44 Air cleaner 45 Intake throttle 46 Intercooler 47 Oil Supply pipe 48 Oil return pipe

Claims (2)

In a cooling device for an electrically assisted turbocharger in which a motor case is attached to a bearing housing that supports the turbocharger's turbo shaft,
A cooling chamber for the motor formed in the motor case ;
A bearing portion cooling chamber formed in the bearing housing ;
A communication oil passage formed at an upper portion of the cooling chamber for the motor and communicating the cooling chamber for the motor and the cooling chamber for the bearing portion ;
A lubricating oil inlet formed in a lower portion of the motor case ;
A lubricating oil outlet formed in a lower portion of the bearing housing ;
Consists of
The bearing portion for the cooling chamber the lubricating oil filled in the cooling chamber for the motor through the communication oil passage with pressurized lubricating oil from the engine is introduced into the motor for cooling chamber through the lubricant inlet An electrically assisted turbo, wherein a cooling lubrication circuit is formed in which the lubricating oil introduced into the cooling chamber for the bearing portion falls by gravity and is discharged and circulated through the lubricating oil discharge port after being introduced. Charger cooling device. The cooling device for an electrically assisted turbocharger according to claim 1 , wherein the motor case is provided so as to connect the bearing housing and a compressor housing of the turbocharger.

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